Naomichi Yamada (山田直道, Yamada Naomichi), also known by his ringname, Hammer Nao (ハンマー・ナオ, Hanmā Nao), is a semi-recurring character in Hajime no Ippo.

He is a featherweight presumed former professional boxer who was affiliated with the Kamogawa Boxing Gym, before moving to the Hachinohe Boxing Club.

His surname is Yamada. In Japan, surnames are listed before given names.


While Yamada was in school, he would get picked on and would transfer multiple times. When he saw one of Makunouchi Ippo's matches on TV, he became inspired as he saw Ippo would always get up and continue fighting again. Yamada wanted to become strong like Ippo, viewing him as his senpai.


Part I

Two Rookie Kings Arc

Yamada and Ippo first encounter

Yamada meets Ippo.

Yamada was among the trove of aspiring trainees hoping to join the Kamogawa Boxing Gym after its rise to renown in Tokyo and was the only individual to persevere and make it through Takamura Mamoru, Aoki Masaru, and Kimura Tatsuya's roadwork test (albeit slowly and painfully). He was then given the nickname "Geromichi" after throwing up on Makunouchi Ippo's shirt from the roadwork. When Aoki looked into Yamada's wallet, a picture of Ippo was in it, revealing that he was a fan of Ippo. Thus, Ippo was chosen to teach Yamada the basics such as jump rope.

When the day of the Kamogawa gym's big event arrived, Yamada went to the Kōrakuen Hall, knowing that Ippo would show up and began following him. Yamada was shown the waiting room, where he was soon chased away by Aoki after taking too long to say "good luck". He was then shown the corridor that leads to the boxing ring, which Ippo then explained the reason there are glove marks on the wall. Yamada and Ippo were then met with Fujii Minoru and the JBC featherweight champion Date Eiji. After Date and Ippo had a conversation, Yamada and Ippo went to the audience seats and watched Takamura, Aoki, and Kimura's matches where all three won.

Ippo and Yamada after spar with Date

Yamada talks to Ippo about his past.

When Ippo received a sparring request against Date, Yamada went with Ippo to the Nakadai Boxing Gym, watching the spar and acting as his second. After the spar, Yamada talked with Ippo about how he used to get bullied at school and how he looks up to Ippo for being strong, wanting to be strong like him. Yamada was then shocked when Ippo told him that he had a similar past, making Yamada become moved, viewing Ippo as the "role model of all the wimps in the nation." Later, when Ippo was fighting against fifth ranker Okita Keigo, Yamada watched the match where Ippo would win by knockout.

Speed Star Arc

Yamada winning his Pro Test

Yamada winning the spar at the Pro Test.

When the Kamogawa gym had the idol, Kumiko Morita interview the boxers about their hopes in boxing, Yamada seemed to be a fan of her as he asked for her autograph. Later, after sparring with Ippo, Yamada left the gym for his Pro Test at the Kōrakuen Hall. Yamada was nervous after passing the written exam, however, he passed the Pro Test spar after downing his opponent. When he got back to the gym and Kamogawa Genji revealed the entry list for the Class A Tournament, Takamura invited Yamada to go with the rest of the gym to the annual training camp to catch up to Aoki and Kimura.

Yamada being called a curse

Yamada being called a "curse".

While Ippo was unable to attend the training camp due to his mother's illness, Yamada went with the rest of the gym to the training camp. He was referred to as a curse by Takamura, as Yamada's presence coincided with Kamogawa joining the troupe and a typhoon cancelling their only day at the beach. Yamada was worried that Ippo might quit boxing due to his mother's illness. When Yamada and the rest of the gym came back, Ippo was at the gym, surprising everyone. Later, while Ippo was training to defeat Saeki Takuma, he had Yamada try to hit him while Ippo used an out-boxer's footwork, which Yamada could not hit him. When Ippo was about to decide to go back to his old style, Yamada suggested otherwise and wanted him to try again. Ippo asked Yamada to put on a tougher face, causing Yamada to use a squinted look. Even though Ippo told him to not do that, Yamada's look made Ippo come up with an idea to go against Saeki. Yamada later watched Ippo, Aoki, and Kimura's matches in the first round of the Class A Tournament where all three won. Yamada then celebrated with them at the Gaiant Echo Karaoke.

Class A Tournament: White Fang Arc

Yamada getting informed about moving

Yamada learning about the moving date.

After the celebration at the Giant Echo Karaoke, Yamada expressed how he admired Ippo's liver blow and wished to use it but does not know how to perform it.After Ippo demonstrated the technique for Yamada, Yamada shortly left the group so that he could go home, thanking them for everything. When Yamada got home, his mother informed him that they would be moving in two days, asking if Yamada was okay with it as he gets picked on every time they move and he would be unable to go to the Kamogawa gym. Yamada reassured her that he was okay with it, and that his memories of Tokyo will be his treasure. His mother apologised, but Yamada told her that being with the Kamogawa gym members changed him, and felt that if he got picked on again, he will be okay.

Yamada leaving the Kamogawa gym

Yamada leaving the gym, giving his farewells to everyone.

Two days later, Yamada told Kamogawa his farewells. Yagi Haruhiko informed Yamada that everyone was waiting in the basement, surprising Yamada. When Yamada entered the room, he was told to spar against Takamura, Aoki, Kimura as a farewell party. With Ippo as his second, Yamada fought against the three, ending each spar with a loss, but the three noticed the results of his training during the training camp. Ippo then got into the ring, wanting to spar for one round with Yamada to not be forgotten. Thinking that it would be his last spar with his senpai, he intended to go all out, as did Ippo. Ippo ended the spar by hitting Yamada with the technique Yamada told him he admired, the liver blow. With the farewell party over, Yamada took a shower at the gym, reminiscing at the areas he was punched at by each member that he will never forget. When it was time to leave, Yamada told everyone farewell, as everyone saw him off.

Proof of Power Arc

Yamada later moved to Aomori, where he joined the Hachinohe Boxing Club and continued his training. Two years later he comes back to Tokyo in order to challenge Ippo for the Japanese featherweight title with a new appearance and demeanour under the ringname "Hammer Nao". With only a short career and only being ranked 7th, he is seen as the underdog and his coach cautioned him against Makunouchi's power, citing his previous boxer's career-ending injuries.

Ippo vs Hammer Nao

Ippo vs Hammer Nao Match Poster

During his preparation in Tokyo, Yamada pulls off an eerie, intimidating personality, throwing back Kimura and Aoki's wishes and stating that they were no longer his senpai. During the weigh-in, he declares that he will take the belt from Makunouchi, refusing his handshake. Makunouchi responds by stating that he never taught Yamada how to take the belt. Despite this show of intent, it turns out to be a bluff as Yamada nearly breaks down from nervousness and tells his coach that he intends to retire after show Makunouchi his strength.

Yamada is overwhelmed in the first round, being knocked down twice by a surprisingly aggressive Ippo. It turns out, however, that Ippo was desperate to end the fight quickly to spare Yamada. Yamada identifies Ippo's body as a weakness and aims for it. Unable to break through Ippo's guard, Yamada demonstrates how he managed to claw up the rankings by executing subtle fouls, pulling Ippo's guard away with his hand and delivering Solar Plexus Blows. Ippo shows his superior experience and stands up to Yamada, knocking him out in the second round.

Suffering his first loss and lamenting on how Ippo was still miles stronger than he was, Yamada followed on with his initial plan of retirement, but ultimately chose to continue boxing after Ippo's encouragement.

Part II

Under Siege Arc

Yamada was later seen at the Hachinohe Boxing Club with trainer hand mitts and his hair beginning to grow and eyebrows when Takamura was travelling around Aomori. Locals came to ask for Yamada's help in moving an old man's truck out of a ditch. When Yamada arrived to the scene, he saw that someone had done so already. When the old man described that the man who helped was a champion with a big hairdo, Yamada remembered only one person who fits the description, but deduced that there was no way Takamura would be in Aomori.

Match History

Match History
# Result Record Date Opponent Location Time Type Notes
9 LOSS 8-1-0 1994-08-20 Japan Makunouchi Ippo Tokyo, Japan 2(10), 2:42 KO "Proof of Power" - JBC Featherweight Title Match


  • VS Takamura Mamoru 1R KO LOSS (Farewell Party)
  • VS Aoki Masaru 1R KO LOSS (Farewell Party)
  • VS Kimura Tatsuya 1R KO LOSS (Farewell Party)
  • VS Makunouchi Ippo 1R TKO LOSS (Farewell Party)
  • VS Unknown Featherweight Boxer 1R KO WIN (Pink Shirt in anime)
  • VS Unknown Featherweight Boxer 1R KO WIN (Blue Shirt in anime)
  • VS Unknown Featherweight Boxer 1R KO WIN (Green Shirt in anime)



Yamada when he was part of Kamogawa gym.

Yamada has pale skin, muscular body, long black messy hair, long moderately thick eyebrows and a large prominent nose. His eyes are large with dark coloured pupils. He has a rather meek facial expression.

When Yamada went by the ring name "Hammer Nao", he modified his appearance to that of a rugged, ugly and fearsome boxer. His head and eyebrows were shaved, his face was twisted to show a considerable amount of dimples to appear more menacing. A shadow rested over his dark eyes, and his left ear had pieces missing. Subsequent to his first loss against Ippo, Yamada began growing back his hair and eyebrows.


When he joined the Kamogawa gym, he was an extremely shy, meek and incompetent trainee at the gym, Yamada has had a lengthy history of being bullied and shunned by others for his appearance and demeanour. Nevertheless he is shown to be kind and encouraging to others and views Ippo with utmost admiration due to the latter's kind treatment towards him and their similar pasts. During his professional license certification, he bore a striking resemblance to Ippo during his own certification, albeit more stressed.

Returning with the ring name "Hammer Nao" however, Yamada's personality is viewed to have changed drastically. He is shown to be guiltless and menacing, often glaring at others and provoking them (evident in his encounter with Aoki and Kimura). He now dislikes being thought of and referred to as a kouhai and apprentice of Kamogawa gym. Yamada seems to have matured as well, and shows a good amount of seriousness towards boxing. However, he silently continues to admire and respect the strength of his former senpai Ippo.

Subsequent to his first loss against Ippo, Yamada has been shown to recover some of his former attitude and meekness, gradually reverting back to his old self.

Boxing Abilities

A boxer with no particular talents to speak of, Yamada had crawled his way through his matches to challenge those of higher ranking. He fights in the standard orthodox peek-a-boo style, relying on subtle fouls during in fights to win his way through challenges. He is also well known for his powerful body blows, but regardless, he is a boxer shown to possess well-trained strength, endurance and spirit. His fight footage shows a grasp of basic boxing tactics, with Ippo noting that Yamada had learned how to read his opponent's move and use appropriate in-fighting techniques such as the Liver Blow.

Takamura mentioned that the two years Yamada had spent away from the Kamogawa gym had been spent well running, with Yamada possessing great leg power, vital for his signature body blows.

He debuted as a junior welterweight, where he fought two matches, before fighting three at lightweight, and another three at junior lightweight. Ippo notes that Yamada 'didn't know what it was like to lose' during their fight - implying he won all his matches at these weights.



Unlike many other gifted characters of the series, Yamada has no natural talent to speak of. Kamogawa describes him as an unskilled boxer. Yamada himself noted that his boxing style involves taking too many hits and predicted that his career would be a short one.

He is largely inexperienced with boxing, having never felt the pain of a loss until his match against Ippo. His movements are also (in Ippo's eyes) quite slow and readable. To compensate for this, Yamada has a tendency to perform extremely subtle fouls at close range to land his signature Solar Plexus Blow. In the final moments, Yamada executed his one-two combination and Liver Blow as he had learned from Ippo, but this was easily blocked, with Ippo returning the exact combination with damaging results, showing the gap between the two boxers.



  • His nickname Geromichi comes from the Japanese word Gero, which means vomit, and -michi from his given name Naomichi. -Michi roughly translates to "path". Takamura explains the nickname as meaning "He who walks the path of vomiting".
  • In an interview included as a Volume 61 extra, Morikawa mentioned - "Geromichi was based on my assistant at the time.  His personality was just like that, but his face was more like when Geromichi's was when he challenged Ippo (laughs)."

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