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

He is a Japanese featherweight 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.

Part I

Two Rookie Kings Arc

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 and Kimura's roadwork course (albeit slowly and painfully). He is then given the nickname "Geromichi" after puking on Ippo's shirt from the workout. It is made apparent that he shows great respect for Ippo, and the latter becomes his senpai afterwards.

Yamada looks up to Ippo with great respect. During Ippo's spar against Date Eiji, Yamada acted as Ippo's second and observed Ippo's strength, though he had an exaggerated view of Ippo's strength in comparison to the Japanese Champion. Yamada reveals to Ippo that he took up boxing because he was bullied at school, mirroring Ippo's beginnings.

Speed Star Arc

Yamada participates in the Kamogawa Gym summer training camp as Ippo was unable to attend due to his mother's illness. Yamada was referred to as a curse by Takamura, as Yamada's presence coincided with Coach Kamogawa joining the troupe and severe storm weather cancelling their only day at the beach.

Yamada's highlight at Kamogawa Gym was to prepare for and pass his pro boxing license test. Despite being very nervous, and among jeers from observers, Yamada managed a knockdown on his opponent and passed the test. Shortly after this, Yamada leaves Kamogawa Gym due to his mother's work. As a farewell, all of his senpai treat him to one last sparring session to remember them by, with Ippo gifting him with his hardest blows.

Proof of Power Arc

Yamada moves to Aomori, where he joins the Hachinoe Kentou-kai boxing gym and continues 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 demeanor 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.

Part II

Siege Card Arc

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. Yamada is later seen with re-grown hair and eyebrows when Takamura is wandering around Aomori. Some local children come to ask for his help in moving an old man's truck out of a ditch, but Yamada realises that someone had done so already. He is left wondering who it was, deducing 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 JapanMakunouchi 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 Naomichi when he was part of Kamogawa Boxing Gym.

As a member of the Kamogawa Boxing Gym, Yamada sported a very meek and unpleasant appearance. He had a pale skin tone and a body built muscular for boxing, long black hair, long moderately thick eyebrows and a large prominent nose. His eyes are large with dark coloured pupils.

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 Makunouchi Ippo, Yamada starts growing back his hair and eyebrows.


First shown to be an extremely shy, meek and incompetent trainee at the Kamogawa Boxing Gym, Yamada has had a lengthy history of being bullied and shunned by others for his appearance and demeanor. Nevertheless he is shown to be kind and encouraging to others and views Makunouchi 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 Makunouchi during his own certification, albeit more stressed.

Returning as 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 Masaru and Kimura Tatsuya). He now dislikes being thought of and referred to as a kouhai and apprentice of Kamogawa Boxing 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.

Fighting Style

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 lie when Geromichi's was when he challenged Ippo (laughs)"

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