Mr. Koike
Chara koike




Mrs Koike (mother)




More than 55 kilograms

First appearance

Hattori saves Kenichi from his teacher

Mr Koike is a schoolteacher and the son of Mrs Koike.

Physical appearance Edit

Mr Koike is thin and not very tall, with curly brown hair and rectangular glasses. He usually wears a blue suit, though sometimes he wears a white shirt and black trousers. He is rarely seen without a briefcase.

Personality Edit

Mr Koike is a mostly reasonable teacher, though at times he can be overbearing and unfair. He can be very shy in front of girls, and went on two failed dates, though he found stability in the form of Aiko-sensei.

Despite being a figure of severity in front of his students, deep inside, Mr Koike is a downtrodden character who lives in fear of his mother and her cakes.

Relationships Edit


Mr Koike, despite his flaws, cares for his students and their wellbeing. He is paticularly close to Yumeko Kawai, who is known for her intelligence.

Mr Koike also gets on relatively well with Kenichi Mitsuba, though he is unafraid to tell him off for his misdeeds. He

Kenichi and his mother recieve Mr Koike

often visits his home to talk to his parents, and mostly ends up being chased out by Hattori and the gang.

Kanzo and Shinzo HattoriEdit

Mr Koike is a good friend of Hattori's and often confides in him for help. Hattori does so, and gets the job done. He is often asked to impress Aiko-sensei, though it can consist of searching for archives as well. 

Mr Koike also has a good relationship with Hattori's little brother Shinzo; he consoled him when he lost his way home, and also offered to take him back. Shinzo, in return, punished the gang by crying loudly when they attacked Mr Koike, thinking he had kidnapped Shinzo.


Mr Koike has a complex relationship with his mother. She occasionally comes to stay at his house, and bakes cakes for him, not knowing that they are his least favourites. Despite all this, she dotes on her son and takes care of him. Mr Koike also looks after his mother when she comes to visit.

It was once implied that he had a son. If he does, then he possibly has a good relationship with him, too. 

Quotes Edit

  • "Kenichi!" (catchphrase)

Other information Edit

  • Mr Koike enjoys collecting butterflies.
  • Mr Koike is good at solving Rubix cubes.


Portrayal Edit

Mr Koike was voiced by Issei Futamata.

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