Wiki Ippo
Wiki Ippo

Haruhiko Yagi (八木晴彦, Yagi Haruhiko) is the manager of the Kamogawa Boxing Gym who used to be professional boxer at the same gym and a mahjong player. While he wasn't succeeding in boxing, he was extremely skilful at mahjong and fishing.

His duties as a boxing manager primarily consist of publicity and match booking, but he also takes part in managing the finances, selling merchandise, and occasionally assists with the training.


Yagi as a boxer.

Yagi was a master fisherman and a professional mahjong player that was unrivalled. When he fishes or plays mahjong, his personality changes, his face turns demonic looking, and some call him the "King of the Underworld" (闇の王, Yami no Ō), or simply "Yami" (闇, Yami), meaning "Darkness". He is so skilful at both activities that it has been said that he could become the world champion of fishing and he did not lose once for twenty years at mahjong. Additionally, numerous fishing ponds and all mahjong parlours put up "No Yagis Allowed" signs, with the fishing ponds doing it because they lost so many customers due to Yagi was catching all the fish.[3][2] While he was a professional mahjong player, he had Ōi Takachan and Murakami Jen as pupils, and helped the owner of the Otakugon start his business. At some point, Yagi was a professional boxer at the Kamogawa gym, having joined around the same time as Miyata Senior. However, despite his passion, he lacked any natural talent to survive as a professional and suffered a string of losses. When Miyata was the JBC featherweight champion, Yagi was having a losing streak, so Miyata invited him to go fishing to cheer him up. Yagi proceeded to beat him in fishing while wearing a demonic expression, frightening Miyata.[4]

Yagi would later retire to become the manager of the Kamogawa gym. While Miyata was the OPBF featherweight champion, he lost in his seventh title defence against Randy Boy Senior and was sent to the hospital. As everyone began to leave Miyata's side at the hospital until only his son Miyata Ichirō remained, Yagi visited and would never forget Ichirō's face.[5]


Part I

Early Days Arc

Yagi and Kamogawa talking about the gym's history.

Yagi and Kamogawa Genji, while watching a world match on the TV, talked about how they haven't raised a world champion since the Kamogawa Boxing Gym opened. Yagi informed Kamogawa that Takamura Mamoru brought a newcomer. When Kamogawa assigned Makunouchi Ippo to spar against Miyata Ichirō, Yagi watched the spar, concluding that despite Ippo's loss, he has great determination. After Ippo won the second spar against Miyata, Yagi and Kamogawa were shown how Miyata barely got hit with the uppercut by 1cm.

When Miyata left the gym, Ippo's power from the spar two months ago was not showing. Kamogawa suggested to have Ippo go with Takamura, who's match is in a week, much to Yagi's dismay. Yagi and Kamogawa announced Ippo's opponent for his pro debut as Oda Yūsuke. Yagi revealed the details of Oda's fight record and fighting style to everyone.

On the day of the match, Yagi noticed that Ippo's name on his trunks is "IPO" instead of "IPPO". Yagi stood at the ringside as a cornerman for Ippo's match. After Ippo's win, Yagi, along with the others, celebrated at the Sugar Ray. When Ippo had his second match against Fujiwara Yoshio, Yagi was one of the cornermen in the match that Ippo won.

Rookie King Tournament: First Rounder Arc

Yagi and Kamogawa learning about Ozuma sending his sparring partner to the hospital.

Yagi received the schedule for the East Japan Rookie King Tournament and showed it to the gym, revealing that Jason Ozuma is Ippo's first opponent. Yagi told Kamogawa that Ozuma sent a sparring partner to the hospital after a hook hit him. On the day of the match between Ippo and Ozuma, Yagi was on of the cornermen, with Ippo winning at the end.

Seeing a fired up Ippo spar with Aoki Masaru and Kimura Tatsuya, he noted how Ippo was influencing the two eight rounders. When the boxers came back from their one week training camp session, Yagi showed the poster of Takamura's JBC middleweight champion match against Yajima Yoshiaki and Ippo's match against Kobashi Kenta. Yagi got excited at the thought of the gym having someone going for a Japanese title in ten years. On the day of the match, Yagi was one of the cornermen for Ippo and Takamura's matches, where they both won. Yagi celebrated Ippo and Takamura's win with everyone.

Rookie King Tournament: Finals Arc

Yagi hugging Ippo as he wins the Rookie King Tournament.

When Aoki had a match that was after Ippo's next opponent, Hayami Ryūichi, Yagi was one of his cornermen. The match ended with Aoki winning. When the day of Ippo's match against Hayami arrived, Yagi was one of his cornermen, with the match resulting in Ippo winning. After the match and outside Kōrakuen Hall, Yagi noted how Ippo worked hard and now got to the promised place to get to Miyata.

Mashiba Ryō fought and defeated Miyata in the semi-finals. This caused Ippo to injure his fist in rage. Yagi noted how Ippo was frustrated due to not sparring in a while due to his injured fists, and warned Kamogawa to watch his fists for the fight. When Ippo and Mashiba's match arrived, Yagi was one of the cornermen for Ippo. Ippo won the match, ultimately winning the East Japan Rookie King Tournament.

All Japan Rookie King Tournament: Rocky of Naniwa Arc

Yagi celebrating Ippo's win against Sendō.

Yagi, along with Kamogawa, left the gym for Thailand in order to look for middleweights for Takamura. When Yagi came back, he learned that Ippo was planning on drugging his fist. Yagi attempted to stop Ippo, wanting his fist to heal fully before fighting again, however, Kamogawa explained that he is too stubborn to listen. Ippo decided to fight Sendō Takeshi despite his fist injury, with Kamogawa only allowing him to if he has the ability to fight on the day of.

Upon arrival to Osaka, Yagi and the others arrived to the Ishino Boxing Gym for Ippo to spar against lightweight class Komori. When the day of the match arrived, in Ippo's waiting room Yagi noticed the different red shorts on Ippo. When the match began, Yagi was one of Ippo's cornermen, with Ippo winning the match and All Japan Rookie King title. Yagi and the rest of the Kamogawa Gym crew celebrated Ippo's win.

Two Rookie Kings Arc

Yagi after Ippo's win against Okita.

While Takamura, Aoki, and Kimura had a match scheduled on the same day, the Kamogawa gym became busy, with Yagi having a line of people wanting to join the gym. When Takamura decided to let all the newcomers do roadwork with him, Yagi became worried. Yagi was one of the cornermen for Aoki, Kimura, and Takamura's matches, where all three won. Later, Yagi received an invitation by Nakadai from the Nakadai Boxing Gym for Ippo to spar against JBC featherweight champion Date Eiji in three days, which he then notified Kamogawa. The day after Ippo came back from the spar against Date, Yagi received a call from Nakadai requesting Ippo to fight against Okita Keigo. When he notified Kamogawa and told him the fight was in one month, as his previous opponent could not make it, Kamogawa accepted. Yagi explained his worries, however, Kamogawa reassured his worries and told him how Ippo's eyes had changed after fighting Date.

Speed Star Arc

Yagi and Kamogawa announce the Class A Tournament schedule.

Yagi announced that a TV station was coming to the gym to interview the boxers. Yagi congratulated Yamada Naomichi after he passed the pro test. He then revealed the Class A Tournament's entry list. Yagi noted how their were seven featherweights who dropped out when Alexander Volg Zangief entered. The next day, Yagi urgently informed Ippo that his mother was sent to the hospital due to collapsing. On the day of the Class A Tournament, Yagi was one of the cornermen for Ippo's match against Saeki Takuma and one of the cornermen for Kimura and Aoki. The matches resulted in all three winning.

White Fang Arc

When Yamada had to move away from Tokyo, Yagi gave him his farewell and informed him that everyone was waiting for him downstairs for a farewell party. Yagi was one of the cornermen for Aoki's semifinal match of the Class A Tournament against Jackal Itō, and Kimura's semifinal match of the Class A Tournament against Ryūzaki Takeshi. Both of their matches resulted in a loss, losing the Class A Tournament. When Ippo's Class A Tournament finals was scheduled to be against Volg, Kamogawa had Ippo undergo intense training. When Kamogawa expressed his worries to Yagi about potentially breaking Ippo and losing all respect, Yagi reassured him that everyone knows he would not do that, and all of the boxers word hard to impress him. During Ippo's match against Volg, Yagi was his cornerman. Ippo then won the match, winning the Class A Tournament.

Challenge for the Throne Arc

When the Champion Carnival for Takamura's match against Tamaki Atsushi arrived, Takamura was over the weight limit. Yagi noted how it was difficult to lose weight in the winter. When Takamura barely passed the weight limit, the match began, with Yagi was one of the cornermen. Takamura then won the match.

The night before Ippo's title match against Date, Kamogawa and Yagi reminisce when Ippo first joined the gym. Yagi believed that Ippo will answer Kamogawa and him as always and become a champion. When Ippo's match against Date arrived, Yagi was one of Ippo's cornermen. The match ended with Ippo losing.

Road Back Arc

Yagi witnesses Ippo using the Dempsey Roll.

The next day when Ippo returned to the gym, he informed Yagi the evaluation's results that showed no signs of brain damage, relieving Yagi. When Kamogawa collapsed due to overwork and went to the hospital, Yagi was there while the doctor gave the report. Yagi told Ippo, Aoki, and Kimura to continue training while he looked after Kamogawa since the three boxers have a match coming up soon. During Aoki's match against Snake Thomas, Kimura's match against Pone Morocotte and Ippo's match against Ponchai Chuwatana, he was there as one of their cornermen where they all won and was shocked when he saw Ippo use the Dempsey Roll.

Hot Rod Era Arc

Yagi attended Sendō's title defence against Saeki and watched in awe as Sendō defeated Saeki in one round.

Mountain Training Arc

Walking away from the Osaka Prefectural Gymnasium after watching Sendō's match against Saeki, Yagi was greeted by Sendō who asked to let him fight Ippo as soon as possible. Yagi told Sendō that there had to be arrangements with his gym. Kamogawa confirmed that he would let Sendō fight Ippo, however, Sendō stated that the Dempsey Roll would not work on him before leaving.

Yagi training Takamura.

After the Naniwa gym approved of Ippo fighting their champion, Sendō, Kamogawa later decided to head to the Pension Yoshio as a training camp. When they arrive to the pension, they meet Nekota Ginpachi. Yagi was tasked to catch fish for dinner, which he completed and made for dinner that night. The following day, Yagi was shocked when Kimura and Aoki rushed back from roadwork and informed him that Ippo was attacked by a bear. However, Ippo came back with a dog, which Nekota confirmed to be his dog, Hachi. Kamogawa announced to everyone at the training camp that he would be splitting the group for individual training. Yagi was grouped with Takamura, with one training method being multiple rounds of Takamura running with Yagi on his back. After Ippo finished his wood chop training, Yagi participated in Kamogawa's teaching of "punching without punching, the Sakki. When Kamogawa and Nekota began fighting over who won the draw, Yagi revealed their record being two wins, two losses, and one draw that neither of them could accept.

On the final day of the training camp, when Takamura was late coming back from his road work, the boxers wonder if he met a bear and if a bear had a weakness. Yagi confirmed that the forehead is the bear's weakness. On the final night of the training camp, Takamura returned wounded with a bear claw mark on his chest, claiming to have knocked out a bear. Yagi then ate a bear nabe that Nekota made for the final night. The next day, Yagi left with the rest of the group and returned to the Kamogawa Boxing Gym. When Takamura, Aoki, and Kimura had a match against Itō Takaaki, Boy Allade, and Nefuma Ozca respectively, Yagi was their cornerman where all three boxer's won. After celebrating at the Sugar Ray, Nekota stayed at the gym, and after five days, Nekota began to show his training skills, impressing Yagi.

Lallapallooza Arc

Yagi as Ippo's second during his title match.

One month before Ippo's title match against Sendō, Yagi put posters up on the Kamogawa gym's windows. Yagi then explained the meaning of "Lallapallooza" to Takamura, Aoki, and Kimura. Later, Yagi ran out of tickets while handing tickets out for fans at the Kamogawa gym and told the group to purchase them at the hall, however, they were sold out as well. He then encouraged Ippo to take the belt due to the tickets for the match being sold out. The day before the match, Yagi and Kamogawa went to the weigh-in with Ippo where they met the champion Sendō. After the two passed their weight check, Yagi, Kamogawa, and Ippo prepared to leave before being stopped by Sendō on the way out in order to speak with Ippo. On the day of Ippo's title match, Yagi was a cornerman for the fight. During the second round when Yagi wondered how Ippo was getting beaten in power, Kamogawa answered how Sendō's body may appear bigger due to boxer's being able to gain weight pass their weight limit right before a match.

Yagi and the new JBC champion Ippo.

In the third round, while Ippo was not able to hit back while getting attacked, Yagi wished for Ippo to come back to Kamogawa as he has high expectations of him, knowing that Ippo still had something that he had not used yet to go against Sendō. In the fifth round after Ippo's second down, Yagi compared the way Ippo fell as when he fell during his match against Date as Kamogawa got ready to throw in the towel. Ippo then defeated Sendō in the seventh round, becoming the JBC featherweight champion. Later, Yagi went to The Sugar Ray where Ippo's celebration party was held. Yagi introduced Ippo to everyone and announced that it was also his birthday.

Execution Arc

When Ippo returned to the gym, Yagi informed him that Takamura, Aoki, and Kimura were in Kamogawa's office, telling Ippo to go in there also, as it was about his first JBC title defence due to the annual Champion Carnival starting. Later, Yagi put up the posters for Kimura's title match against JBC junior lightweight champion Mashiba. When Kimura's title match arrived, in the waiting room, Yagi encouraged Kimura, who was thinking of retiring if he loses, to do his best. Yagi gave Aoki permission to be Kimura's cornerman for the match. After Kimura lost the match and claimed to have retired, Yagi told everyone at the gym that Kimura should be arriving to get his final reports and scores for the match and to see everyone to say goodbye. Kimura, however, soon decided to not retire.

First Step Arc

When Ippo's first title defence match in the Champion Carnival against Sanada Kazuki began, Yagi was one of Ippo's cornermen for the match which resulted in Ippo's victory.

Proof of Power Arc

Yagi showing the tapes of Yamada's matches.

While Ippo's second JBC featherweight title defence match was coming up, Yagi introduced the new member he scouted, Itagaki Manabu, to the Kamogawa gym members. Yagi later showed videos of Ippo's opponent, "Hammer Nao", which was a ring name of Yamada Naomichi, giving details of the former gym member's boxing career. After receiving the match poster, Yagi displayed the match poster on the gym's exterior, noting the absence of Yamada on the poster was due to his name being near worthless for bringing in customers. On the day of the weigh-in, Yagi went with Ippo where he met Yamada.

When the day of the match arrived, Yagi was one of Aoki's cornermen in the semifinals against Paddy Magramo, which Aoki won. Yagi then was one of Ippo's cornermen for his title defence match. During the second round, Yamada broke Ippo's guard by pushing it with his hand to land the solar plexus blow. While Yagi claimed that it was against the rules as Yamada's using his opened hand to open the guard, Kamogawa praised Yamada for it as a foul had not been called. Ippo then won the match in the second round, defending his title a second time.

Battle of Hawk Arc

Yagi announcing Takamura, Itagaki, and Kimura's matches.

When Takamura, Kimura, and Itagaki were at the beach for their training camp, Yagi and Kamogawa attended to watch over their training. Later, when Kamogawa announced to his gym members that Takamura has a world title match in December, and before that, a match in October along with Itagaki's debut match and Kimura's comeback match, Yagi added that Ippo has a match as a semifinal to Takamura's world title match at the Ryōgoku Kokugikan. When everyone including Aoki was fired up for their upcoming matches, Yagi informed Aoki that he had no matches, much to Aoki's dismay. When the matches in October arrive, Yagi was one of Itagaki, Kimura, and Takamura's cornermen for their matches where it resulted in a loss against Makino Fumito, winning decision against Arman Alegria, and winning ring out against Morris West respectively. Yagi then witnessed Bryan Hawk's arrival to Takamura's room in the hall, becoming shocked of the champion's reason for coming to Japan was to enjoy Asian women.

Yagi with Takamura as he wears his new WBC belt.

Later, Yagi attended Hawk's public spar at the Kinoshita gym where Hawk pulled his punches until his women arrived, dominating his sparring partner. On the day of the weigh-in and press conference, Yagi went with Takamura to the weigh-in where Takamura barely passed at full limit before being mocked by Hawk. The next day, Ippo and Takamura's match arrived, with Yagi teaming up with Umezawa Masahiko to sell Takamura-themed merchandise. When it was time for the matches, Yagi was one of Ippo's cornermen for his match against Yi Yon Su, and then Takamura's in his title match against Hawk which both ended in wins, resulting in Takamura becoming the new WBC champion.

A week later, a package arrived to the Kamogawa gym, which Yagi confirmed to the gym members was ordered by Takamura himself. When it was opened, it was revealed to be a large bust Statue of Takamura.

Part II

Submarine Wars Arc

Yagi announcing everyone's matches.

When Itagaki won for the first time in his second match against Baraki Haseo, Yagi was a cornerman for the match. Later, Yagi announced the matches for early spring, with Ippo defending his JBC featherweight title for the fourth time and Aoki's JBC lightweight title match for the Champion Carnival, Itagaki's Rookie King Tournament match, and Takamura's first WBC middleweight title defence. When Ippo went to Kamogawa about why he has turned down Miyata's match requests without telling him and questioned Kamogawa's reasoning, Yagi reminded him that Kamogawa is not the type to run away, suggesting for him to get strong enough to satisfy him. After Ippo left, Yagi and Kamogawa talked about the Dempsey Roll being Ippo's greatest weakness against Miyata's counter. Yagi theorised that the opponent's strategy will be stopping the Dempsey Roll and then everyone would figure out a way to stop it. Later, Yagi discovered on a magazine article that Ippo's next opponent, Shimabukuro Iwao, claimed he would destroy the Dempsey Roll, with Yagi realising the statement would apply pressure to Ippo.

Yagi and Kamogawa with Ippo after winning against Shimabukuro.

Later, Yagi and Kamogawa showed everyone a video of Shimabukuro fighting Okita Keigo at last year's Class A Tournament where Shimabukuro won. Yagi revealed details about Shimabukuro during which. When Ippo and Kamogawa formed a strategy of strengthening the Dempsey Roll's speed and power, Yagi pointed out that increasing the speed and power of it would increase the dangers as well. When the day of Ippo's match against Shimabukuro arrived, Yagi noticed Ippo being more calm in his changing room and wonders if Ippo thinks the match will be difficult. When the match began, Yagi was one of Ippo's cornerman for the match. The match resulted in Ippo's victory.

Comic Show Arc

Ippo revealing his acknowledgement of the Dempsey Roll's weakness to counters.

After Ippo recovered from his match against Shimabukuro and returned to the gym, he revealed to Kamogawa and Yagi how he noticed the Dempsey Roll's weakness to counters, which was Kamogawa's reason for turning down a fight with Miyata. As Ippo left mentioning his outlook for future fights would be hard, Yagi commented on how he is maturing.

When the weigh-in for Itagaki's first round of the East Japan Rookie King Tournament and Aoki's JBC lightweight title match against Katsutaka Imae arrived, Yagi attended Itagaki's weigh-in. The next day, Kamogawa arrived to the Kōrakuen Hall for Itagaki and Aoki's match. Kamogawa was a cornerman for Itagaki's match, which ended in a knockout win for Itagaki. Yagi then was a cornerman for Aoki's title match. The match ended in a draw, resulting in Imae keeping the belt. While Aoki was tricking Imae with his Play Dead act, Yagi and the other seconds were fooled as well, with Yagi almost throwing the towel before being stopped by Shinoda Tomoyuki. When Aoki revealed looking hurt was just an act to draw out Imae's stamina, Yagi noted that he did not realise it was just an act. The match then ended after the ten rounds were over. A decision was made and the match ended in a draw, resulting in Imae keeping the belt and Aoki losing.

Dragon Slayer Arc

When Kobashi arrived the Kamogawa gym, wanting to meet Ippo, Yagi informed Ippo. Yagi arrived at the Ryōgoku Kokugikan and was one of Takamura's seconds in his first WBC junior middleweight title defence match against Larry Bernard, which ended in Takamura's victory. Later, Kamogawa had Ippo pick one out of four challengers for his fifth title defence. When Ippo picked Sawamura Ryūhei despite him and Kamogawa knowing that Sawamura is the Dempsey Roll's natural weakness, Yagi mentioned to Kamogawa about how much Ippo has grown and was shocked that Kamogawa doesn't rule out on Ippo losing. Later, Yagi arrived with Ippo to the Kōrakuen Hall for his weigh-in against Sawamura. The next day, Yagi was one of Ippo's seconds for his match against Sawamura. After the fourth round, Yagi examined the damage after Ippo's Dempsey Roll was defeated, finding that his mouthpiece is bloodied and the inside of his mouth is shredded. Ippo later won in the seventh round.

A Passing Point Arc

Yagi and Shinoda teamed up in a fishing competition.

When Kamogawa used the prize money from the Sawamura match to take everyone fishing at the Makunouchi Fishing Boat, it turned into a fishing competition, with teams of two consisting of Takamura and Kamogawa, Aoki and Kimura, and Yagi and Shinoda. When it began, Yagi and Shinoda were beating everyone by a long shot. Takamura and Kamogawa were having trouble catching fish, leading an angry Takamura to stomp his feet as he tried to fish, shaking the boat and making Aoki go off board. When Takamura thought he got one, he reeled up an Aoki instead. When they ran out of fishing spots, they returned and gave the caught fish to Makunouchi Hiroko for her to cook. After everyone gathered, Kamogawa revealed that Takamura would challenge the WBC title for the middleweights, Aoki and Kimura have matches, Miyata has an OPBF title defence match before Takamura's title match, Itagaki continues his East Japan Rookie King Tournament, and Ippo is instructed to continue his recovery.

Yagi and Takamura fishing.

When Imai came to the Kamogawa gym to spar with Ippo, Yagi watched the spar, where Ippo struggled against Imai. Despite their fellow gym member had trouble with Imai, Yagi noticed Aoki and Kimura were fired up after seeing it. After Takamura got back from his training camp, he demanded a fishing competition against Yagi on his homeland. After Kamogawa agreed so that Takamura can take Yagi down, Yagi and Takamura commenced their fishing competition. During the competition, Yagi held back to let him so that Takamura could prepare for his match in high spirits. However, Takamura kept missing his chances to catch a fish. Eventually, Takamura got angry after Yagi caught three and jumped into the water to grab three fish, ending the match in a draw, When he got back to the gym, everyone gathered as Yagi revealed the cards for Takamura's WBC middleweight title match. He revealed that along with Takamura facing champion David Eagle as the main event, Miyata would face third ranker Medgoen Dachboy as his fourth OPBF title defence as the semi-final, Kimura would face a Filipino national champion Eleki Battery, and Aoki would face the Indonesian national champion Papaya Dachiu. Yagi warned Aoki about Papaya's destructive Coconut Punch.

During Itagaki's quarter-final in the East Japan Rookie King tournament, Yagi was one of Itagaki's seconds for the match, which ended in Itagaki's victory. Later, Yagi informed Ippo and Itagaki that Kamogawa and Shinoda took Takamura, Aoki, and Kimura to a training camp. When the match poster for Takamura's world title match arrived, he plastered it on the gym's windows and explained what the English saying of "a passing point" means in Japanese and what it means to Takamura. When Eagle arrived to Japan, Yagi, Kamogawa, and Ippo went to the Kawahara gym to see Eagle spar. When they get there, Yagi was shocked to see Eagle giving autographs to local children. Yagi watched Eagle spar and was surprised to see Eagle not holding back. Afterwards while walking to the gym, Yagi saw Takamura beat children who wanted an autograph. Yagi went to the Yokohama Arena for Takamura's weigh-in with Eagle.

Yagi in the ring as Takamura celebrates his win as the new middleweight WBC champion.

The next day, Yagi went to the Yokohama Arena for the Kamogawa gym members' matches. Yagi was one of Kimura and Aoki's seconds for their match against Eleki and Papaya respectively. The matches ended in a draw. Yagi was then one of Takamura's seconds in his match against Eagle. After the match ended in Takamura's victory and he became the new WBC middleweight champion, Yagi gave both the WBC junior middleweight and middleweight belts to Takamura as he and everyone celebrated in the ring. Afterwards, with the belts in their cases, Yagi tried to hand them to Takamura, however, he wanted Kamogawa to keep them instead.

Spirit of a Weed Arc

Three days later, Yagi arrived to the gym and inform Takamura that he has two interviews, three TV features, and two requests for commercials. When Itagaki's East Japan Rookie King Tournament semi-finals match against Makino Fumito began, Yagi was one of Itagaki's seconds for the match, which ended in Itagaki's victory. Later, Yagi informed Ippo that Kamogawa wanted to speak with him at his office. After Kamogawa explained that Ippo would be fighting in one month if he accepted, Yagi warned Ippo to not take the challenger lightly because of his low ranking.

Under Siege Arc

Though Yagi advised for Ippo to think about deciding whether he should have or postpone a match against Karasawa Takuzō, Ippo was ready, and Kamogawa accepted Karasawa's request. Later, Kamogawa showed Ippo videos of Karasawa's matches and Yagi commented how Karasawa knows how to use the space in the ring and footwork, suggesting for Ippo to break Karasawa's rhythm fast. That night, Kamogawa wondered why Ippo took the match, which Yagi reminded him that Ippo wanted to start over and try something, while predicting that Ippo could rack up on body blows and win in the later rounds. On the day for the weigh-in, Kamogawa noted how Ippo's face made it seem like he was unfocused and missing something, which Yagi suggested it was from something from what the reporters who Kamogawa kicked out said and wondered if Ippo would be able to hide the face when he sees Karasawa at the weigh-in.

Yagi after Ippo's match against Karasawa.

The next day, Yagi went to the Kōrakuen Hall for Ippo's weigh-in with Karasawa. The next day, Yagi went to the Kōrakuen Hall for Ippo's seventh JBC featherweight title defence match against Karasawa, where Yagi was one of Ippo's seconds. The match ended in Ippo's victory in the second round by knockout. Yagi held Ippo up in the air in celebration of the victory.

Phantom Card Arc

As Aoki was angry at Takamura for feeding him the pickled squid that made him sick and was tired of Takamura's actions, he tried to split the gym into two factions, with Takamura being alone and Aoki and the rest of the gym along with him as Broccoman having the children of Japan on his side. Aoki's side changed from a lot of support to none when Yagi and Shinoda revealed to everyone about how Broccoman's popularity has severely gone down due to recent reports of Aoki leaving the Kōrakuen Hall while covered in faeces. Later, when Itagaki's East Japan Rookie King Tournament finals against Imai were coming up, Yagi gave Itagaki videos of Imai's matches. Yagi watched Itagaki spar against Ippo in his last spar before his match.

Yagi uses the "Ima no Isu Naisu" pun at Itagaki's match against Imai.

When Itagaki's match against Imai in the East Japan Rookie King Tournament arrived, Yagi went to the Kōrakuen Hall to be one of Itagaki's seconds for the match. During the fifth round, Kamogawa instructed Shinoda to have some words to fire Itagaki up, but Shionda is out of ideas. They ask Yagi instead. When the gong sounded to end the fifth round, Itagaki was about to fall at his corner, but Yagi quickly caught him with the chair, exclaiming a pun of "this chair is nice" (Ima no Isu, Na~isu (今のイス、ナ~イス)), resulting in a scolding from Kamogawa and a glare from Shinoda. The match lasted to the end of the final sixth round, where Itagaki won by decision, becoming the Rookie King of the east. Afterwards, Yagi went to the locker room as Itagaki was taken away to the hospital. At the East Rooking King ceremony, Yagi informed Ippo that Itagaki was doing fine at the hospital

When Yagi, Kamogawa, and Ippo left the venue, they were approached by Sendō and the West Rookie King, Hoshi Hiroyuki. When Hoshi was stating his intentions on wanting to fight Ippo for the JBC title, Yagi mentioned that he has no right to, as he is unranked. Hoshi responded that once he defeats Itagaki at the All Japan Rookie King Tournament, he would have the right soon enough. After Hoshi and Sendō left, Ippo asked Kamogawa to let him relinquish the JBC title in order to fight his goal, Miyata. Yagi thought it was too sudden. but Kamogawa revealed that he would do it and send a challenge to the OPBF champion, Miyata. Later, after Kamogawa got off the phone with Miyata father and they agreed to have a match between Ippo and Miyata in Spring, Yagi believed that the happiest person about the match is Kamogawa.

Father's Back Arc

Yagi with Kamogawa as he reveals Ippo's seventh JBC title defence.

At the Kamogawa gym, Yagi was being made fun of for his chair pun that he used in Itagaki's match against Imai until Kamogawa entered and had Yagi give Takamura, Aoki, and Kimura training under his order to take back his dignity. Yagi order the three to do three sets of hitting the sandbag for ten minutes, however, in Japanese, it came out in an accidental pun, making him get laughed at more by the three. As Kamogawa called Ippo to his office, Yagi went with him. As Kamogawa revealed that Ippo would be fighting in the Champion Carnival for his seventh JBC title defence, Ippo was disappointed. Yagi mentioned that Ippo's match schedule has been aligned with Miyata's schedule. After Ippo left excited that the match is unofficially set for Spring, Yagi mentioned to Kamogawa how overjoyed he is and that Miyata must be happy about their dream match as well. Later, when Itagaki got released from the hospital, Itagaki wanted to immediately look at videos of Hoshi, however, Yagi wondered why. Shinoda revealed to Itagaki that the gym has decided to resign him from the All Japan Rookie King Tournament due to his injuries.

Later, as Kamogawa revealed details to Ippo about his upcoming opponent, Take Keīchi, Yagi noted how Take seems to be able to take a lot of punches. When Ippo's weigh-in with Take arrived, Yagi went to the Kōrakuen Hall. When Take arrived, he appeared sick. After the weigh-in, Ippo was worried about Take, until Yagi laughed as Kamogawa revealed to him that it was fake, while Yagi believed that Kamogawa was the one that was affected the most since he is upset.

Yagi with Ippo in his match against Take.

The next day Yagi went to the Kōrakuen Hall to be one of Ippo's seconds in his seventh JBC title defence match against Take. After the first round, Ippo mentioned that Take told him that he figured out his weakness, however, Yagi believed that Take was bluffing. During the second round, Yagi was shocked to see Take switch to the Southpaw stance and urged Kamogawa to come up with a southpaw strategy as Ippo's rhythm has broken. After the second round, Yagi noticed how bloody Ippo's mouthpiece is, afraid that Ippo may lose. During round four, after Kamogawa was frustrated with himself when he realised the reason for Ippo's punches not getting at Take, Kamogawa wanted Yagi to hit him, however, Yagi did not want to. During round five, Yagi gave Kamogawa an ice pack after Kamogawa had Ippo hit him in the face and noted how Ippo seemed excited to go back and fight. Ippo defeated Take during the sixth round by knockout.

Chaos Arc

At the Kamogawa gym, Yagi revealed to the gym members that Takamura has his first WBC middleweight title defence match as the main event against a third ranker, a world bantamweight title match as the semi-final, and Aoki and Kimura as openers in a rematch against the Indonesian champion, Papaya and the Philippines champion, Eleki respectively. Later, Yagi went to the Ryōgoku Kokugikan to be a second for Takamura, Aoki, and Kimura's match. Yagi was a second for Aoki's rematch against Papaya, and Kimura's rematch against Eleki, which both ended in a draw. Yagi was one of Takamura's seconds in his first WBC middleweight title defence match against Richard Fox, where it ended in Takamura's round one knockout victory.

Seiken Arc

Yagi revealing to Itagaki about a match against Hoshi.

After Sawamura fought Mashiba and the match ended in Sawamura retiring due to a motorcycle accident after the match and Mashiba being suspended from boxing for some time, Yagi warned the Kamogawa gym members that they should be careful as it is not uncommon for boxers to get into car accidents. After Kamogawa had Itagaki and Shinoda come to his office. Kamogawa revealed to them that the West Rookie King Hoshi sent a request to go against Itagaki. Hoshi had two rules: Kamogawa mentioned that the first rule was that they would have to fight in Osaka, while Yagi revealed that they promised to give Hoshi a right to challenge Ippo for his JBC title if Itagaki is defeated by him. After Itagaki left, Yagi noted how the OPBF is selecting an interim champion as both fists being broken takes awhile to heal and that if Itagaki loses, Ippo wouldn't be able to relinquish his belt until he fought Hoshi. When Itagaki's match to advance from being a six-rounder in order to fight Hoshi arrived, Yagi went to the Kōrakuen Hall to be one of his seconds, where he wins by decision.

Yagi as a second in Itagaki's match against Hoshi.

After seeing Ippo shadowbox with Miyata as his opponent, Yagi mentioned to Kamogawa that it was a good idea to turn down the invitation for the OPBF interim title if his focus is only Miyata, since the second ranker in the OPBF, Randy Boy Junior has a strong reputation. Later, Yagi and Kamogawa received resignation paperwork from Shinoda, as he felt that he wasn't able to tap into Aoki and Kimura's potential, and if Itagaki loses against Hoshi, he would resign. When Itagaki's match against Hoshi arrived, Yagi went to the Osaka Prefectural Gymnasium to be one of Itagaki's seconds for the match.Before the match began, Yagi informed Takamura, Aoki, Kimura, and Ippo that due to Aoki and Kimura's comments, Shinoda has decided to retire if Itagaki loses. When the match began, Yagi was one of Itagaki's seconds. The match ended in Itagaki's victory by knockout in the first round.

Scratch Arc

Yagi learning that Miyata has cancelled his match with Ippo.

When Miyata's father came to the Kamogawa gym, Yagi learned that his son has decided to put his priority into maintaining his OPBF title, wanting to fight the interim champion rather than the promised match against Ippo. That night, Yagi mentioned to Takamura how Kamogawa was looking forward to the match as much as anyone else and that both him and Ippo were looking forward to the same thing and now that thing has disappeared, and he doesn't know where the two will look to or where they will go. Later, as Yagi put up the match posters for the main event of Takamura's second WBC middleweight title defence match against Rickey Mouse, Fujii Minoru approached him and asked when Ippo's next match will be as there must be an unnecessary void inside of him due to recent events with Miyata. However, Yagi informed him that Ippo has been away from the gym.

Later, when Yagi informed Kamogawa that Ippo is outside the gym, Kamogawa tried to ignore him, but got irritated as Ippo paced back and forth outside and had him come in. After Ippo apologised and requested for Kamogawa to let him keep boxing, Kamogawa decided to have Yagi call any champions in the OPBF and schedule a match in one month time in order to begin a road for Ippo to become the unofficial OPBF champion. Yagi was able to contact the Thailand's national champion, Jimmy Sisphar, who Yagi felt is too dangerous to fight against.

Yagi at Ippo's match against Sisphar.

As Takamura, Aoki, Kimura, and Itagaki came back from a training camp and learned that Ippo would be fighting Sisphar, Yagi showed them Sisphar's boxing record and explained his "Scratch J" nickname. When the weigh-in arrived, Yagi went with Ippo to the Kōrakuen Hall where they meet Sisphar. When Ippo's match against Sisphar arrived, Yagi went to the Kōrakuen Hall to be one of his seconds. During the second round, as Ippo was about to fall at the corner, the gong rang and Yagi caught Ippo's fall by placing the chair expertly under him. The match ended in Ippo's victory by knockout in the fourth round.

Operation World Domination Arc

At the gym, Kamogawa wondered where Takamura was, and, after hearing from Kimura that he went out to find a finishing move, Yagi added that he hasn't seen him sparring either. When Takamura returned, Yagi witnessed Takamura showing his Beetle's Uppercut, demonstrating it on Aoki. When Itagaki, Kimura, Aoki, and Takamura had a match, Yagi went to the Ryōgoku Kokugikan to be their second. Yagi was one of Itagaki, Kimura, and Aoki's seconds for their match against Alex Harker, Michael Gehon, and Padawan Yoda respectively, where all three Kamogawa gym members won by knockout. Yagi was one of Takamura's seconds in his second WBC middleweight title defence match against Rickey Mouse. The match ended in Takamura's victory by knockout in the first round. Walking out of the venue, Yagi asked Kamogawa if he was mad, as Takamura was wearing an embarrassing outfit, but Kamogawa claimed he wasn't, wanting to take everything at heart.

Later at the gym, as Itagaki, Aoki, and Kimura were shocked when their rankings didn't move up despite getting a knockout victory, Yagi explained that their matches probably weren't included, but may be included in next month's rankings. After hearing from Ippo about meeting Randy Boy Junior's shady manager, Yagi figured it was Mr. Sakaguchi and informed Ippo to go see Fujii for videos on Randy. Later, after realising that Randy Boy Junior is the son of Randy Boy Senior, who destroyed Miyata's father's career, Yagi explained to the gym members about how he was good with both hands and how he won against Miyata's father. As the gym members wondered if Miyata can win, Yagi mentioned how Miyata's father was defeated when there was no information about Randy, but now they have information, so nothing unexpected will happen.

Winner Takes All Arc

Yagi hearing Tsukahara's story.

Yagi was shocked when the police department called the Kamogawa gym to have him pick up Kamogawa from the department. Yagi took a train to the police department in Sendai, Miyagi with Ippo as he explained that Kamogawa was the one to cause the incident as he was supposed to speak with an old friend and get tapes of Ippo's next opponent as the man's boxer fought him. When they arrived to the police department, they meet Kamogawa, who got released and the victim of Kamogawa's cane assault, coach Tsukahara of the Tsukahara gym. As Yagi and Ippo apologised to Tsukahara, he pleaded for Kamogawa's forgiveness, much to Yagi's shock. Yagi, Kamogawa, Ippo, and Tsukahara went to a restaurant as they listened to Tsukahara's story of how his boxer, Fukui Kyōsuke fought Ippo's next opponent and won in a fixed match, with his boxer retiring shortly after due to the shame of his opponent losing on purpose. Tsukahara pleaded to Ippo for him to beat his next opponent, Filipino champion Malcolm Gedo before leaving.

When Yagi, Kamogawa, and Ippo returned to the Kamogawa gym, Yagi watched as Ippo sparred against Fukui, who wanted to make memories before retiring. After Ippo won by a one round knockout per Kamogawa's order, Yagi went to the rooftop and discussed with Kamogawa about the spar. Yagi assumed that Kamogawa played the bad guy by insulting Tsukahara in hopes to get Fukui not to retire. Kamogawa noted how fearsome Gedo must be to be able to fool everyone by faking his defeat against a Japanese ranker.

Yagi discussing about the decision to accept the match against Gedo.

Yagi, Kamogawa, and Ippo reviewed Gedo's video on his match against Fukui. They watch Gedo's high levelled defensive and manoeuvring abilities, along with Fukui being surprised when he hits Gedo, which Ippo revealed that it is his "magic" to disrupt one's depth perception. As Kamogawa agreed with Ippo's decision to accept the match with Gedo, Yagi tried to get them to think first since they don't have a plan and are emotional. After Kamogawa and Ippo disagreed, Yagi decided to accept the match against Gedo. Later, when Yagi entered the gym, Kamogawa was accidentally hit with a cane by Takamura. Kamogawa angrily told him to throw the chunk of wood away, making him leave. Yagi figured that Takamura brought the cane to give Kamogawa as a gift since his cane was taken by the police. Later in the gym's office, Yagi informed Kamogawa that Gedo's side gave the okay and said that they would be good for tomorrow. Surprised, Kamogawa assumed that they must be after Ippo's world ranking, however, Yagi revealed that they didn't know who Ippo was and are only focused on the prize money, which made Kamogawa furious.

Yagi holding Kamogawa back in their meeting with Gedo.

Yagi and Kamogawa took Ippo to the Tōhō gym to spar against Mashiba, much to Ippo's dismay and the spar ended with both boxers noticeably injured. Later at the gym, Gedo and his manager arrived to discuss their match with Ippo. Yagi had to hold Kamogawa back as Kamogawa was angered as Gedo was only interested in talking about money and mispronounced Ippo's name on purpose. Gedo and his manager left after Kamogawa ultimately decided that it would be a winner takes all for two million yen in one month at the Kōrakuen Hall. When Īmura Mari arrived at the gym, Yagi explained that the money wasn't for promotional purposes, and that the risk is very high since if Ippo loses, the gym would lose a lot of money, Ippo's momentum, and his world ranking.

Yagi arriving to the ring with Ippo in his match against Gedo.

When the day of Ippo's match against Gedo arrived, Yagi went to the Kōrakuen Hall to be one of Ippo's seconds. During the first round, Yagi and Kamogawa were confused as to why Ippo threw a big swing when Gedo moved out of the way with both arms stretched out, however, Kamogawa figured out the trick and shouted to Ippo to look at Gedo's feet. After the fifth round, Yagi became worried as Ippo has stopped saying that he won't lose and now says he won't get knocked down while Kamogawa is only trying to raise his spirit, thinking that neither of them can see a way to achieve victory. After round six, Yagi suggested for Ippo to quickly sit down as Kamogawa has a plan and gave him water to gargle.

During round seven when Ippo barely missed a follow up attack after hitting Gedo with a Heart Break Shot, Yagi feared that the one and only chance was lost. With 45 seconds left to the end of the seventh round, Kamogawa decided to dip his hands in a bucket of ice and orders Yagi and Shinoda to tell him when there is five seconds left, preparing to do the last thing he can do for Ippo. When five seconds are left, they tell Kamogawa, to which Kamogawa takes his hands out of the ice bucket. After the seventh round and Kamogawa put his ice cold hands over Ippo's swollen eyes to let him see, Kamogawa's hands became numb, and he gave the towel to Yagi for him to stop the match when he gives him the signal. During round eight when Kamogawa gave Yagi the signal as Ippo was about to get hit with a big punch, Yagi threw the towel as Ippo dodged the attack, however, Kamogawa caught the towel. Yagi cheered as Ippo defeated Gedo in the eighth round by knockout.

Red Lightning Arc

When Team Itagaki's pro test arrived, Yagi went to the Kōrakuen Hall to watch them. However, they lost in the end. Outside the venue, since Itagaki, Aoki, and Kimura were entering the Class A Tournament and Itagaki met Saeki and Karasawa who were also entering, Itagaki was worried about facing out-boxers that are faster than him. Yagi asked Ippo of his thoughts, which he thought that he lacks experience compared to Saeki and Karasawa. While Yagi believed that Itagaki has the potential, it will be a hard match win or lose. When the Otowa gym requested for Itagaki to spar with Randy, Itagaki wanted to, but Yagi claimed that Kamogawa isn't at the gym. Shinoda decided to let him go, and when Ippo wanted to go, Yagi thought it would be a good idea since Randy may cross paths with Ippo. Later at the Kamogawa gym, Yagi informed the gym members that Takamura was doing a spar. He explained that as a promise between Kamogawa and Takamura, if Takamura defeated three opponents in a spar at the same time without getting hit, Takamura can go for his third weight class world title match, but if he gets hit, he has to do his third WBC middleweight title defence. After Takamura sparred against the three Japanese middleweight rankers and he got hit, it was decided his next match is the title defence. Yagi revealed to the gym members that Takamura's third WBC middleweight title defence opponent in April would be Ronald Duck, Aoki and Kimura would be openers, and Miyata would face Randy in the semi-final.

When Sendō came to the gym, he revealed his "beat-down list", which Miyata was one of the names on it for him to spar against to help him train to fight Mexicans. Ippo decided to take him to the Kawahara gym for Miyata and Sendō to help each other before being stopped by Kamogawa and have Itagaki take Sendō instead. Due to Kamogawa not wanting to let Ippo go see the spar, Ippo became depressed until his depression annoyed the others at the gym, making them order him to go around and buy them outlandish items, with Yagi ordering for him to get him a issue of a magazine as a hint for him to watch the spar. On the day of the Takamura, Aoki, and Kimura's weigh-in and Takamura's press conference, Yagi went to the Kōrakuen Hall for the weigh-in and then ate at the De La Hoya before going to the joint press conference for Takamura and Miyata.

The next day, Yagi went to the Yokohama Arena, where he was one of Kimura's seconds in his match against Sim Rex, which was stopped by a doctor in the fifth round and Kimura lost the decision, and Aoki's match against Ponsa Kureck, where he lost by decision after ten rounds. Yagi went to Takamura's room in the venue while Miyata fought against Randy. After Miyata defeated Randy, Yagi arrived to the ring to be one of Takamura's seconds for his third WBC middleweight title defence against Duck, where Takamura won by knockout in the tenth round.

Second Coming of Death Arc

As Itagaki was sparring to get ready for his upcoming match as the semi-final for Mashiba's OPBF lightweight title match, he wanted to spar with Ippo, however Ippo was told by Kamogawa before that he can not spar with Itagaki, but Yagi gave the okay for two rounds. When Itagaki's match against Kaonar Pachiyoso arrived, Yagi went to the Kōrakuen Hall to be one of Itagaki's seconds, where the match ended in the second round by Itagaki's knockout victory.

In the Jungle Arc

Yagi encouraging the Class A Trio to win the Class A Tournament.

At the Kamogawa gym, Kamogawa revealed that along with Aoki, Kimura, and Itagaki having a match in the Class A Tournament soon, Ippo also has a match in two months, which Yagi revealed as the Indonesian featherweight champion with a record of only three fights. Yagi showed Ippo, Aoki, Kimura, and Itagaki the video that the Indonesian champion's side sent, however, it seemingly only showed nature shots with the champion not present anywhere in it. After Ippo took the video with him and left, Yagi expressed to the gym members about the concern that Kamogawa has about the person who sent the video, Miguel Zale. Later at the Kamogawa gym, as Aoki, Kimura, and Itagaki discussed their upcoming Class A Tournament match, Yagi revealed that Aoki and Kimura only need to win twice to win the tournament since there are only four fighters entering in both of their weight classes, encouraging them to win.

When the day of Ippo's weigh-in arrived, Yagi went to the Kōrakuen Hall with Ippo and met Miguel and the Indonesian champion, Wally. As Wally and Miguel were hugging Ippo and Kamogawa, Yagi explained to Fujii and Mari how they are being hugged against their will despite that Ippo tried to enter the weigh-in with some intensity. After the weigh-in, Kamogawa stayed while Yagi and Ippo left. Yagi asked Ippo if Wally left a strong impression, which Ippo claimed he's strong.

Yagi with Ippo in his match against Wally.

The next day, Yagi arrived to the Kōrakuen Hall for Ippo's match against Wally. Yagi acted as one of Ippo's seconds when the match began. After the first round, Yagi asked if Wally's punches were light since he claimed he was okay after getting hit multiple times. Ippo answered that they were sharp. During the second round, Yagi was shocked as Wally hit Ippo with a Smash. During the third round, as Ippo brought Wally to the red corner, Yagi was shocked as he watched Wally grab the ropes to push himself back to escape. After the fourth round, Yagi told Ippo to wipe Wally's smile off his face and to not let it end with him laughing down at him. As the fifth round ended, Ippo was at the corner and almost fell when the gong rang, however, Yagi expertly placed the chair under him, catching his fall. During the sixth round, Yagi asked Kamogawa what Ippo should do, however, Kamogawa had no answer but is bracing himself to stop the match if Ippo goes down. During the seventh round. Kamogawa noticed Wally having trouble jumping around. Yagi wondered why, but Kamogawa did not know. Ippo defeated Wally by knockout in the eighth round.

Chronos Arc

Yagi with Itagaki in his match against Karasawa.

After seeing Itagaki get hit a lot in a spar against Kimura for his training against Karasawa, Yagi asked Shinoda what is wrong with Itagaki. Shinoda explained that Itagaki can't bring out his full potential unless in a match and fully focused, not knowing his condition until he fights. On the day of the first round of Aoki, Kimura, and Itagaki's Class A Tournament, Yagi arrived to the Kōrakuen Hall to be one of their seconds. Yagi was one of Itagaki's seconds as his match against Karasawa began. During the second round as Itagaki was in a pinch, Yagi asked Shinoda if he is going to give advice to Itagaki, however, Shinoda mentioned that he is prioritising the experience he will gain from the fight. After Itagaki won by knockout in the second round, Itagaki asked what his knockout time was, which Yagi revealed was two minutes, thirteen seconds. Yagi was one of Aoki and Kimura's seconds in their match against Jackal Itō and Ryūzaki Takeshi respectively, where Aoki and Kimura win by decision. Kamogawa watched the match between former JBC lightweight champion Katsutaka Imae and Iga Shinobu which decides who Aoki would be fighting in the Class A Tournament finals, revealing to the gym members of Iga's record. After Iga's effortless victory against Imae, Yagi explained to the gym members how Iga started with only decision wins before having a string of knockout wins.

Blind Step Arc

Yagi revealing details about Kojima.

After Kamogawa revealed to the gym members that Ippo has an eighth JBC featherweight title defence, Yagi explained that even though he is unranked, he is a former ranked lightweight who has fought in a featherweight match recently, and mentioned that his name is Kojima Hisato. Later, Yagi, Kamogawa, and Shinoda gave the gym members an overview of the upcoming matches, with Takamura's fourth WBC middleweight title defence match and Ippo's eighth JBC featherweight title defence match in October and in November it will be the Class A Tournament finals. Yagi assisted Ippo's training by holding a sandbag with Shinoda, pushing it against Ippo as Ippo tried to out push them. Yagi and Shinoda were able to knock Ippo down with the sandbag at first until Ippo successfully pushed them down after some attempts.

On the day of Ippo and Takamura's weigh-in and Takamura's press conference, Yagi arrived at the Roigal Hotel. When Yagi went to Ippo's weigh-in, he was shocked that his opponent, Kojima Hisato looked skinny from the weight control. After Ippo and Takamura passed their weight check, Yagi rushed to attend Takamura's press conference with his opponent, Peter Rabbitson.

Yagi entering the ring with Ippo in his fight against Kojima.

The next day when Ippo's eighth JBC featherweight title defence match against Kojima and Takamura's fourth WBC middleweight title defence match against Rabbitson arrived, Yagi went to the Ryōgoku Kokugikan. Yagi arrived to the ring to be one of Ippo's seconds and, after a minute and a half passed with neither fighter moving, Kamogawa figured that Ippo must be building up strength for a punch with his full weight behind it, which Yagi wondered if Ippo is planning to end it with one punch. The match ended in one round after Ippo defeated Kojima with a one hit knockout. As Takamura's fourth WBC middleweight title defence was about to begin, Yagi arrived to the ring to be one of his seconds. After Takamura won by a one punch knockout in the final twelfth round, Kamogawa wanted to scold him and Ippo, however, Yagi informed him that Takamura already left.

Speed Zone Arc

Yagi discussing the Class A Tournament finals.

Yagi and Kamogawa watched Mari interview Ippo about his match with Kojima. Afterwards, when Kamogawa noted that his match with Kojima confirmed that some of the something he planted in Ippo took root, Yagi thought he is talking about the destructive power shown in the knockout, however, Kamogawa mentioned that he meant before the knockout where Ippo recovered from the hit he took and attacked back. Kamogawa believed that while the world may view Ippo as a no name fighter, the weapon he is building will make the world have to notice if it shapes up well, contemplating that the time for the seal to come off may be soon. Yagi figured that he means the seal for the Dempsey Roll, wondering if Kamogawa has done something to the technique. Later, Yagi and Kamogawa discussed with Shinoda about Aoki, Kimura, and Itagaki's training for the Class A Tournament finals. Yagi mentioned how it must be hard training the three all day, which Shinoda responded that Kamogawa has it harder due to training Ippo and Takamura. As Kamogawa mentioned how tough of an opponent Saeki is, Yagi worryingly asked what Itagaki's chances of winning are. Shinoda answered that he believes that Itagaki has great potential.

Yagi at the ring with Itagaki in his match against Saeki.

When Itagaki, Kimura, and Aoki's Class A Tournament finals arrived, Yagi went to the Kōrakuen Hall. As Itagaki's match against Saeki began, Yagi was one of Itagaki's seconds. During the third round as Itagaki began to have the advantage, Yagi asked Shinoda what happened. Shinoda revealed that playing Shiritori with him after the second round was to get him to relax. Yagi mentioned from experience that Shiritori requires a lot of thinking, however, Shinoda knew that it was easy for Itagaki since he always read books about animals, fish, and insects when he was young. After the third round, Itagaki noted that he still couldn't see out of his right eye. Yagi pointed out that he could still land many hits on Saeki, wondering if his depth perception is off or not. Itagaki replied that it was like he was looking at the ring from above. During the fourth round, as Shinoda noted how Saeki is blocking Itagaki's attacks by guarding in a way to block punches he can not see, Yagi theorised that Itagaki would eventually hit Saeki as he is good at finding gaps in defences. Yagi mentioned to Kamogawa and Shinoda how he remembered reading that in football, that some players can visualise the field from an aerial perspective and batters in baseball some claim that they see the ball not moving, concluding that some athletes have unusually sharp senses when focused enough. After Itagaki defeated Saeki by knockout in the fourth round, Yagi had Itagaki lean on him as he walked to the venue's room. There, Yagi informed Aoki and Kimura that they are up next and left Ippo to stay with Itagaki.

When Kimura's match began, Yagi was one of his seconds where it ended in Kimura's loss by decision. When Aoki's match against Iga began, Yagi was one of his seconds. After the sixth round, Kamogawa deemed Iga a master of positioning. As Yagi noted that Iga isn't moving around much, Kamogawa added that Iga is making his opponent move by manipulating Aoki into danger zones without him realising it. Yagi commented that that normally doesn't happen unless there's a huge gap in their skill. After Shinoda threw the towel in the seventh round as Aoki collapsed, the match ended in Aoki's loss. Due to the injuries, Yagi went with Aoki as he was taken to the Kawai Hospital, where he heard from Mashiba Kumi that Aoki is in stable condition.

Yagi revealing Ippo's match against Alfredo.

Walking away from the hospital, Yagi expressed how he was glad Itagaki won as it would have been depressing if Iga was made MVP of the tournament. When Ippo was sure that Aoki and Kimura would try again, Yagi was not so sure, explaining how their loses may not be easy for them to overcome as Aoki was defeated in a way that he never seen before and Kimura did not show any enthusiasm and if he had tried in his match, the decision would have been in his favour. Yagi believed that the duo were pushed to their physical and mental limits, and that it is up to them to decide what they do next, but if they continue to do what they always do, he would be against them returning as active boxers. He added that Shinoda may feel responsible for those two, which would make not hard to imagine him quitting too, but no matter what happens, it is a turning point for the gym. Later at the gym, Kamogawa and Yagi revealed to Ippo that they are moving him onto the world stage by having Ippo would fight the second in the world, Alfredo Gonzales, to gain the attention of Ricardo's management.

Proud Wolf Arc

After having watched Volg defeat champion Mike Elliot and become the IBF junior lightweight champion, Yagi went to the Kamogawa gym and expressed to the gym members how Volg's comment of thanking America during his victory interview must have earned him many fans there. As Kamogawa informed Ippo that his JBC title is being relinquished, Yagi revealed that Itagaki would be having a JBC featherweight title match to being the belt back.

Go to the World Arc

When Kamogawa was mitt practising with Ippo, he stopped to tell him to take a break. Ippo, however, claimed he did not need a break which made Kamogawa want to continue until Yagi advised Kamogawa to take a break. As Kamogawa mitt practised with Takamura after the break, Takamura complained that he wants to conquer the super middleweight class. Yagi informed Takamura that the super middleweight class is one of the most competitive, and that there is discussions about an unification match, making negotiations difficult. Later, Yagi gathered materials from a fishing store for Kamogawa to help with Ippo's training against Alfredo by making a glove on a stick that can extend, shrink, and bend.

Yagi walking with Ippo to his match against Alfredo.

When the weigh-in for Ippo's weigh-in with Alfredo and Itagaki's weigh-in for Imai arrived, Yagi went to the Kōrakuen Hall to attend Ippo's weigh-in, where they meet Alfredo. The next day, Yagi went to the Kōrakuen Hall for Ippo and Itagaki's matches. Yagi arrived to the ring to be one of Itagaki's seconds in his JBC featherweight title match against Imai, which ended in Itagaki's loss in the first round by knockout, causing Imai to be the JBC featherweight champion. Afterwards, Yagi went to Ippo to prepare him for his match against Alfredo, informing him that Itagaki is still conscious and that Aoki and Kimura are with him, believing that Itagaki is probably not sure how to face Ippo after not being able to take his belt back. When Ippo's match arrived, Yagi went to the ring to be one of his seconds as his match against Alfredo began.

Yagi with Ippo after he lost to Alfredo.

During the first round, Kamogawa observed that Alfredo is already using a complicated strategy by messing with Ippo's sense of range, which Yagi added that Ippo has to not only pay attention to Alfredo's left, but also his footwork, making it a difficult start for him. After the third round, Ippo asked his seconds why he went down, to which Yagi revealed to him that he went down from a long left hook. During the sixth round as Alfredo tried to land a counter on the Dempsey Roll, Yagi watched in shock and wondered how Alfredo can rush into the Dempsey Roll and if he has studied it thoroughly, however, Kamogawa believed he hasn't since it would have stopped the technique cleanly. In the seventh round, Ippo was sent down by Alfredo's counter. Before the referee could start the count, Kamogawa hurriedly ran up to the ring, resulting in the match ending in Ippo's loss as Kamogawa went to check on him. When Ippo got up by himself, Yagi walked with him out of the ring.

Battle of the Beasts Arc

Yagi discussing Takamura's six weight class conquest with Kamogawa.

When Ippo came back to the Kamogawa gym after his loss against Alfredo, Ippo voiced for his seconds to continue helping him with his boxing. Yagi asked Ippo how his exam went and Ippo confirmed that they claimed he looked good after the exam. After Kamogawa revealed that Takamura is having a WBA and WBC middleweight unification match, Yagi informed everyone that the semi-final matches for it is a world flyweight title match, Mashiba's first OPBF lightweight title defence match, and Sendō's world ranked match while noting how it was difficult to set up since Mashiba and Sendō were arguing over who would go first. That night, Yagi and Kamogawa discussed Takamura's next match and how Kamogawa gave Takamura a condition for moving to the super middleweight class when he wins against the WBA middleweight champion. Yagi became excited over thinking that the gym will have two world belts sitting on the office table.

Yagi at Takamura's corner during his match against Bison.

When Takamura's middleweight unification match against the WBA middleweight champion Richard Bison arrived, Yagi went to the Yokohama Arena and waited for the match to begin as Takamura slept in the venue's room. While waiting, Yagi was thrilled as he heard Sendō and Mashiba being loud in their waiting room as he figured the two rivals would pump each other up before their match, oblivious to the fact that they are arguing with each other. When it became time for Takamura's match against Bison, Yagi arrived to the ring to be one of his seconds. During the second round as Takamura used the Detroit Style against Bison's Detroit style, Yagi assumed Bison will get angry and create a chance for Takamura to gain momentum, however, Kamogawa was not so sure, as Bison is also a world champion. When the third round began, Yagi wondered if Takamura was hurt even though he was acting like he wasn't. Kamogawa informed him that Takamura was unconscious at the corner until Ippo told him to do his best, which made Takamura force himself to put up false bravado after seeing everyone worried about him, continuing to fight with only willpower. Yagi mentioned that Takamura should find a way to recover, however, Kamogawa noted that there is no way to keep away from Bison and that the only way for a chance to win is to find a way to get past the Flicker Jabs. When Takamura landed the Flicker Counter and sent Bison down, Yagi was amazed about the bond between Kamogawa and Takamura as Kamogawa previously told Takamura to ask Bison what to do against the Flicker Jabs. Yagi was told by Kamogawa to save his excitement as Bison is getting up because he spun his neck to negate the impact of the counter.

Yagi with Takamura after his victory against Bison.

After the third round, Yagi noted that Takamura is dangerously close to getting a charlie horse as his weight control leaves him with barely any minerals, noticing that his legs were about to cramp before the round ended. After the fourth round, Takamura requested for his right leg to be massaged as he was about to have a charlie horse at the end of the round. Kamogawa positioned himself to block Bison's corner from seeing Shinoda massage his leg as Yagi gave Takamura water. During the fifth round, Kamogawa observed that Takamura is trying to take down Bison with one punch. Yagi was worried since finding a counter chance against another world champion is risky, which Kamogawa also does not approve. As Takamura kept getting hit by a huge left hook while being able to dodge and attack against every other attack, Yagi wondered if it has to do with a special angle or timing to make it hard to dodge. As Takamura is sent out for round six, Yagi asked Kamogawa if he can see fine, which Kamogawa answered that he can, leading Yagi to conclude that the real problem is his leg. The match ended during the sixth round by Takamura winning by knockout, becoming the new WBA middleweight champion, unifying the WBA and WBC titles. Yagi placed a WBC belt on his shoulder and wrapped the new WBA belt around his waist as he wore the three world title belts to celebrate. After Takamura was interviewed in the ring and made the crowd angry at him due to his haughty attitude toward the crowd, Yagi and the rest of the gym members had to rush out of the ring.

Goals to Reach Arc

Yagi announcing Aoki and Kimura's matches before Iga's title match.

The next day, the gym and Takamura were contacted by cabinet office for Takamura to accept the people's honour award. When the gym members found out, Yagi and Kamogawa confirmed it was true. The gym later got a call back from the cabinet office retracting the offer when Takamura caused a scene where he was seen naked. Later, as requested by Ippo, Yagi got Ippo two tickets to Miyata's seventh OPBF featherweight title defence match for him and Sendō. Later, Yagi, with Shinoda and Kamogawa informed Aoki and Kimura about their upcoming ranked matches that take place as an opener before the main event of Iga challenging the JBC lightweight champion. When Ippo wanted to see the new upgrade that Aoki mentioned, Yagi watched a one round spar between the two, where Ippo gets knocked out by Aoki's new Bell Horn. Afterwards, Yagi, Kamogawa, and Shinoda discussed Aoki and Kimura's next match. As Shinoda was worried about Kimura since he has no motivation at all, Yagi noted that they don't have time to worry and that Kimura has been in the situation before so they should trust in Kimura to straighten himself out.

When Aoki and Kimura's come-back matches arrived, Yagi went to the Kōrakuen Hall to be one of their seconds for their matches. Kimura's match ended in a draw after eight rounds and Aoki wins his match by knockout in the eighth round. Yagi watched Iga's JBC lightweight title match against the champion Ōshima Sōshi in the venue's waiting room. The match ended with Iga's victory by knockout in the sixth round, making Iga the new JBC lightweight champion.

Seeking Heights Arc

Yagi talking to Takamura about Ippo's new Dempsey Roll.

At the Kamogawa gym, when Matsuura and his coach showed up to spar with Ippo, Yagi watched Ippo spar with him, where he was shocked as Ippo showed his Dempsey Roll with a new up and down movement. After the spar, Yagi reflected on how the seed Kamogawa planted inside Ippo is growing and now it is budding. After Kamogawa scolded Ippo about the performance of the Dempsey Roll, Yagi told him how he was a bit harsh, as Ippo found the new Dempsey Roll himself without knowing what Kamogawa was training him for, however, Kamogawa was silent. Yagi went to the rooftop where he meets Takamura. Yagi expressed his excitement about Ippo possibly returning to the ring with his new Dempsey Roll. Takamura didn't care and requested for Yagi to set him up for a super middleweight title match, however, Yagi explained how it has been hard negotiating. Before leaving, Takamura mentioned to Yagi that it would be a bad idea to expect anything from Ippo and that the gym has him, and that is all it needs.

When three potential new members came to the Kamogawa gym, Yagi was excited. However, after the three saw Kamogawa's scolding and Ippo's training, they left, leading Yagi to think it was going to be a bad day until he saw Ippo mitt practise with Kamogawa. After the mitt practise session, Kamogawa went to his office and when Yagi checked on him, Kamogawa gloated on how his hand is screaming in joy. Later, Yagi introduced Ippo's sparring partner, a world ranker and junior featherweight boxer Nagumo Ryūji. Yagi watched the spar where it was quickly stopped by Kamogawa after Ippo went down quickly by Nagumo's lefts.

Yagi discussing with Kamogawa that Ippo may be punch drunk

At the gym's office, Yagi and Kamogawa discussed about the possibility of Ippo being punch drunk. While Yagi did not believe Ippo could be punch drunk as the specialists that Ippo is sent to after every match has found nothing. Kamogawa claimed that they might not have found it yet and that early stage punch drunk may not even show up on the exams, making the answer as to why a boxer can't dodge a mystery. Yagi noted that the one with the most experience with the boxer makes the call, and Kamogawa believed that Takamura may have paid closer attention than him, but Yagi insisted that Takamura's words are only proof and only theory and suspicion. Yagi mentioned how Ippo is deemed tough, however, he goes down many times in his matches and only gets up by pushing himself to his limit, and, with his comeback victories, they may have come at a high price. They decided that the way they will confirm it is by asking Ippo if he experiences any symptoms of being punch drunk.

The next day at the gym's office, after Ippo was asked if he has experienced any symptoms of being punch drunk and he answered that he hasn't, Kamogawa tasked Ippo to draw a straight line on a sheet of paper to prove it. After Ippo draw a straight line, Kamogawa's suspicions were not cleared, with Kamogawa suspecting Ippo still had cumulative damage, so he decided to ban Ippo from the gym for one month. After Ippo left, Yagi told Kamogawa that they should be patient and wait for Ippo to return.

One month later, Yagi informed Kamogawa that Ippo should be returning, however, Kamogawa kept trying to change the subject. The gym members got loud as Ippo was seen walking slowly to the gym, leading Kamogawa to yell at Ippo for him to come inside. After being tested by drawing a straight line, walking in a straight line and partook in a mitt training session with Kamogawa, Ippo passed and was allowed back in the gym and do training. At the office, Yagi expressed his excitement about the new Dempsey Roll Ippo performed during the mitt practise. Later, Yagi gave Ippo the ticket to Naguno's junior lightweight WBA world title match that they received due to Ippo being his sparring partner. Later, Yagi went to the Kōrakuen Hall to be one of Aoki, Kimura, and Itagaki's seconds in their matches. Itagaki's match ended in a decision win, Kimura's ended in a draw, and Aoki ended his match with a knockout.

Later, after Kamogawa had a mitt practise session with Takamura and Ippo back to back, Yagi voiced his concerns about Kamogawa's health when he started coughing. When Kamogawa mentioned that Ippo and Takamura are in good shape, Yagi insisted that they should go ahead with the plan of having Ippo's return match as a semi-final to Takamura's main event match in two months.

10 Months in the Making Arc

When Ippo's opponent for his comeback match was revealed to be the Filipino featherweight champion Antonio Guevara, Kamogawa and Yagi showed Ippo a recording of Antonio fighting Malcolm Gedo which ended in Antonio's victory. While watching the video, Yagi informed Ippo that Antonio is a southpaw. Later, Yagi went to the Roigal Hotel for Takamura's press conference for his WBC and WBA middleweight title defence match against Keith Lycaon and Ippo's come-back match against Antonio. The next day, Yagi went to the Ryōgoku Kokugikan for Ippo and Takamura's matches. In the waiting room before ippo's match, when Takamura asked if Kamogawa was feeling guilty that he could only find a southpaw to fight Ippo, Yagi explained that a southpaw may be a difficult opponent for a return match, but Antonio was the only one who didn't run away from a match with Ippo.

Yagi walking with Ippo to his return match against Antonio.

When Ippo's match against Antonio began, Yagi was one of Ippo's seconds for the match. During the second round, Kamogawa noticed that Antonio's front right foot is keeping Ippo from getting into his range since the feet are positioned in reverse when the boxer is a southpaw. Yagi added that Ippo's new Dempsey Roll has no long ranged punches, requiring him to put an extra step-in to use it. After the third round and as Ippo left for the fourth round, Yagi noted that Ippo is doing a good job, but Kamogawa claimed that the match isn't going like how the previous come-back match went, afraid to see what else will be different. Yagi still believed that nothing bad will happen, wanting to put faith on their boxer. As Ippo went down for the third time while trying to show Kamogawa the new Dempsey Roll, the match ended, resulting in Ippo's loss. In the venue's waiting room, Yagi believed that it was his fault for getting Ippo a southpaw for his return match, however, Shinoda disagreed. Yagi went to the ring to be one of Takamura's seconds in his WBA and WBC middleweight title defence match against Lycaon, which ended in Takamura's victory by knockout in the first round.

Later at the Kamogawa gym, Ippo visited to give his report from the doctor. While Yagi and Kamogawa were relieved that the tests came out clean, Kamogawa asked for Ippo's conclusion, and the latter announced that he will retire because of the risk of being punch drunk if he continues and will instead help with his family business. When Ippo left, Yagi was thankful that Ippo made the decision to retire rather than have Kamogawa carry the burden of having to tell Ippo to retire. Yagi expressed his relief that Ippo is still healthy and that he can work at the fishing boat with some peace of mind.

Part III

Second Step Arc

Two months after Ippo retired, Kamogawa was hospitalised as he was taken ill from a cold. Yagi discussed with Shinoda on what to do and decided to have Kamogawa only focus on training Takamura when he gets back, while getting a trustworthy person to help in the meantime, deciding on having Ippo become a second. After Ippo accepted the request of becoming a second for the gym, he requested for Yagi to get him tapes of Kimura's next opponent. When Yagi went to give him the tapes in the gym, he got chills seeing Ippo shadowbox before giving him the tapes. When Kimura's match arrived, Yagi went to the Kōrakuen Hall and prepared Ippo on how seconds get the ice ready and had Ippo change into a second's outfit. When Yagi went to the ring as Kimura's match was beginning, Yagi wanted Ippo to be on duty to wipe off Kimura's sweat since it is his first time, however, Yagi gave him the chair placing duty by Ippo's request. Though Ippo messed up the chair's placement the first two rounds, Kimura won by knockout in the seventh round. Later, when Aoki and Itagaki's matches arrived, Yagi went to the Kōrakuen Hall to be one of their seconds, where Aoki won by knockout and Itagaki won by a decision. Afterwards, Yagi and Shinoda realised that Ippo is only hard on Itagaki, knowing that Itagaki will know why Ippo has high expectations for him.

Later, when Ippo brought Teru Okazaki to the Kamogawa gym, Yagi was hopeful for Ippo to get him to join the gym, however, when Teru showed a weak punch on the sandbag, Yagi insisted for him to sign up anyway as it would be good for his health, but the boy ran away.

Taihei Arc

Yagi was about to do mitt practise with Kamogawa to warm him up to mitt practise with Takamura, however, Ippo arrived to the Kamogawa gym, and it was decided that Ippo would be the one hitting Kamogawa's mitts instead. Yagi watched Ippo hit the mitts with Kamogawa, reflecting on how nostalgic the sounds are and that they are still in sync. As Ippo was told to go faster, Yagi was shocked as the sound was different due to Ippo not hitting the mitt right and the rhythm is erratic, thinking that Ippo is lagging before realising that that is not the case. After the mitt practise session, Ippo claimed that his reason for visiting was to get a pair of training mitts to help train someone. Kamogawa expressed that Ippo having a disciple is something he would like to see one day, which Yagi agreed as he manages the newcomers, asking Ippo to have him come to the gym soon.

A bald Ippo, who smacked the boy he was training, came back into the gym and asked for Kamogawa in order to say his apologises. In Kamogawa's office, as Kamogawa was giving Ippo his atonements, the two that he wants Ippo to train, Aoki Taihei and Kintarō Kaneda arrived at the gym, with Yagi informing Ippo that Taihei and Kintarō called the gym requesting to enrol and that they heard their story. Once everyone discovered that Taihei and Aoki are brothers, Yagi, Ippo, and Itagaki recognised Aoki and Taihei as being in a TV show called "Heartwarming Special Presents: The Hectic Life of an 11-Person Family". That night, Yagi mentioned to Kamogawa how lively the gym has gotten. Kamogawa noted that watching boxing is another way to learn and that having students will impact his growth. Yagi wondered if the growth is him as a second, trainer, or as a person.

Towards a Resolution Arc

When Takamura's WBA and WBC middleweight title defence match against Michael Goat arrived, Yagi went to the Ryōgoku Kokugikan to be one of his seconds. The match ended with Takamura's victory by knockout in the second round and a proclamation that he will conquer the super middleweight class next. After returning to the gym, Ippo and his students began to run away from the gym in excitement from the match as Yagi noticed that Ippo may have figured something out and wondered how he will be involved with boxing moving forward.

Sendō in Mexico Arc

Yagi discussing Sendō's decision on going to Mexico with Mari and Ippo.

When Mari came to the Kamogawa gym and revealed that Sendō went to Mexico, Ippo assumed that he went there to see Alfredo. Mari explained how the Naniwa Boxing Club's staff tried to have Sendō fight Alfredo after Ippo loss, but Alfredo's side wouldn't respond due to Alfredo refusing to fight any Japanese after feeling like he got trick fighting Ippo for the right to challenge the world and fight Ricardo and not get to fight Ricardo because Ricardo's side doesn't have any interest fighting someone Ricardo beat twice. Yagi voiced that they have the contract in writing that the winner was supposed to have a WBA title fight if they won, but he can't help Alfredo since their the ones with the rights, seeing that Sendō refuses to give up on a match against Alfredo.

Importance of the Support Role Arc

Yagi with Kimura during his match against Junpei.

When the weigh-in for Kimura, Itagaki, and Aoki's match arrived, Yagi went to the Kōrakuen Hall to attend their weigh-ins and was shocked to see Ippo, who was in charge of helping Kimura with his weight control, carrying Kimura while both are bald. After Kimura barely made weight in the reweigh-in, Yagi went with the gym members to the Donaire to eat as Ippo explained Kimura's Dragonfish Blow strategy for his match. The next day, Yagi arrived to the Kōrakuen Hall for Kimura, Itagaki, and Aoki's match. Yagi was one of Kimura's seconds for his match against Yoshimoto Junpei. After the first round, Kimura came to the corner dehydrated. Yagi asked Ippo what they as seconds should do besides massaging his legs and giving him water, reminding Ippo that forfeiting is an option. Ippo decided to continue by shoving ice into Kimura's trunks and using Kamogawa's "Revival Ritual" with the help of Yagi and Shinoda, successfully reviving him to have him continue into round two. Kimura defeated Junpei in the second round by knockout. Yagi was then one of Itagaki and Aoki's seconds for their match, where Itagaki won by decision and Aoki won by knockout in the seventh round.

Ippo in Mexico Arc

When Ippo returned to Japan and went to the Kamogawa gym after being in Mexico and watched Sendō defeat Alfredo and Ricardo defeat Billy McCallum, Yagi was gifted a panda wrestling mask as Ippo explained what he learned in Mexico.

Keith Dragon Arc

Yagi discussing Takamura's stubborn decision of not wanting to fight overseas with the rest of the Kamogawa gym staff.

With Takamura's WBC super middleweight title match against Keith Dragon confirmed and the gym members were discussing the event, Yagi revealed to everyone that it will take place in Japan, making it the first time a world super middleweight title match is hosted in Japan's history, and gave Ippo the champion's profile, which was in English. When everyone noticed that Dragon's hobby is mahjong, Ippo asked if he is good at it. Yagi answered that Dragon heard that there are mahjong pros in Japan, which is why he agreed to fight in Japan, adding that his skills earned him the nickname "Manhattan's Demon King". That night, when Ippo entered Kamogawa's office, Shinoda asked him how Kintarō and Taihei's training has been going, as Yagi informed Ippo that they have been talking about letting them do their pro test and debut, requesting to know their weight classes. Ippo replied that they are not old enough to debut yet, but will be soon, and that he will think of what weight class to put them in. Ippo mentioned how lucky the gym is to have Yagi negotiate with Dragon on coming to Japan, however, Yagi noted that Dragon was happy to be able to play mahjong with the Japanese, making there to be no negotiations to be had. Yagi expressed how he wishes he could have Takamura fight around the world, however, Shinoda explained that Takamura stubbornly chooses to fight only in Japan. Yagi pointed out that he wants the gym to have a match at the Tokyo Dome, suggesting to book Takamura and Dragon's match with Sendō and Ricardo's match to possibly make the Tokyo Dome sell out, however, Yagi had his doubts that they could make them sell out and Shinoda noted that Sendō's rehabilitation for his fist will take a while. Wrapping up the discussion, Yagi offered Ippo to come with him, Shinoda, and Kamogawa to eat dinner as fellow staff members, however, Ippo declined, as his mother is most likely waiting for him with dinner already.

At the Kamogawa gym's office, Yagi answered the gym's phone and heard that Takamura was going to the hospital in an ambulance due to a traffic accident. Yagi, along with Ippo, hurried to the Tokyo Metropolitan Hirokane Hospital. There, they were relieved to see Takamura unhurt, as they learned that Takamura saved a boy from getting hit by an incoming vehicle, and he was in the hospital for the boy since he cracked his ribs while saving him. Later, Yagi watched Takamura spar. After Takamura defeated his sparring partner, Yagi was worried because they have already ran out of sparring partners for him in Japan.

Yagi in a mahjong match between Dragon, Ōi, and Murakami.

Later at the Kamogawa gym, since it was a condition that Dragon set that he has to play mahjong if he comes to Japan, it was decided that former mahjong professional Yagi would be one of the three mahjong players that plays with Dragon. Yagi planned to make sure that Dragon doesn't enter the ring against Takamura in a good mood. Fired up from his blood boiling for the first time in a long time, Yagi changed his manager look to a black suit, shades, and slicks his hair back as he left the gym with his bodyguard, Ippo to the mahjong parlour, Otakugon. When Yagi and Ippo arrived, they were introduced the two other mahjong players by the owner: Ōi Takachan and Murakami Jen, who are mahjong professionals and Yagi's pupils. When Dragon arrived to the Otakugon, the mahjong match between Yagi, Dragon, Murakami, and Ōi began. After Dragon won the first mahjong match, Dragon asked how much is at stake, however, Yagi informed him that gambling is illegal in Japan, but pride will be the thing that is at stake, something that money pales in comparison. When the second match began, Dragon kept getting winning hands while Murakami and Ōi were losing out. Yagi came to a conclusion that he will have to defeat Dragon himself, deciding to use yamiten (damaten). Having thirteen out of fourteen tiles, Yagi drew and laid down the fourteenth tile in hopes it gets him the hand he seeks. When Yagi placed the tile down, it earned him a winning hand. After Yagi and Dragon got a winning hand again, Yagi offered to start gambling with Dragon, one yen per point, however, he was immediately kicked out for trying to gamble, which can get the business shut down. Yagi walked out with Ippo, depressed that he left empty handed and banned again.

Later, Yagi went with Takamura to his press conference for his match against Dragon and ate at the Hirosue afterwards. The next day, Yagi went to the Ryōgoku Kokugikan to be one of Takamura's seconds for his WBC super middleweight title match against Dragon. During the second round, as Yagi and Shinoda saw that Ippo and Kamogawa had an uncomfortable feeling about Takamura, they tried to find the source of their discomfort. However, Kamogawa revealed the source as Takamura being stronger than usual since he has been freed from the shackles of weight control. After Takamura won in the fourth round, becoming the WBC super middleweight champion, Yagi went into the ring with Takamura's champion belts and mentioned to Takamura how stunned he was by what the Gods were doing for Dragon, however, Takamura claims that it wasn't the Gods or luck, but Dragon's fists and techniques. Yagi celebrated with Takamura and the other seconds for Takamura's victory. After Ippo and Takamura leave, Kamogawa told Yagi that it was a great night, which Yagi agreed.

Later, Yagi was called out by Dragon for another mahjong match in order for Dragon to make some memories. Yagi accepted and gathered mahjong professionals Robo and Matsu to play as well. When Yagi went to the Otakugon and the "winner takes all" mahjong match began, Dragon was thrown off his game by Robo and Matsu, and the game ended in Yagi's victory.

Post-Keith Dragon Arc

At the Kamogawa gym, Yagi revealed to the gym mates of his victory against Dragon in mahjong, and noted how despite Dragon losing, his back looked calm and contented. On the day of Mashiba's world title preliminary match, which Itagaki's match against a Filipino ranker is the semi-final of, Yagi went to the Kōrakuen Hall. Yagi was a second of Itagaki during his match. The match ended in Itagaki's victory by decision.


Yagi has black short hair, a large nose, dark eye colour. He is always seen wearing eyeglasses, something he wasn't wearing in his youth.

His attire usually consists of the white KBG t-shirt and black pants. At times, he wears formal suits.


Yagi possesses a gentle and friendly personality as a manager for the gym and its boxers. In contrast to Kamogawa's gruff and strict attitude, Yagi prefers to be more nurturing and optimistic when speaking to the boxers, showing genuine concern for their well-being. That said, it sometimes allows Takamura, Aoki and Kimura to take advantage of his meeker approach (often leading to Kamogawa stepping in with a swinging cane). He often adds ~kun to the end of the names of the Kamogawa gym members.

Despite being quite friendly as a boxing manager, he becomes incredibly competitive and cocky when it comes to sport fishing, more than willing to make bets (and fully aware that he will win them).

Like Kamogawa, he puts a lot of trust in Ippo's ability to fight, though this is not without limits- if the fight has taken a turn for the worse and he feels that a boxer is at risk, he will readily suggest throwing in the towel.


  • "I would love to handle a big match like that at least once, as a manager." - Round 2, while watching a world title match with Kamogawa Genji.


  1. 1.0 1.1 Round 1326, page 8
  2. 2.0 2.1 Round 1326, page 11
  3. Round 513, pages 17-19
  4. Round 513, pages 17-19
  5. Round 754, pages 6-7