‘Kenichi’

Shirahama Kenichi is an average student who has earned the nickname “Weak Legs” from always getting bullied. One day he meets a cute girl named Furinji Miu who helps him build the courage to begin training at a mysterious dojo where she lives. Here Kenichi faces intense training from masters of many different martial arts styles as he attempts to become stronger.

Descriptions taken from AniDB.net