The disturbing footage, which has gone viral on the internet, shows the teacher at Hamamatsu Nittai Senior High School in Shizuoka yelling abuse at the youngster while striking him in front of the other students. And these aren't little taps to the cheek either, they are full-force roundhouse jawbreakers.
The school has admitted it was the second time that day the teacher involved, who has not been named, physically attacked one of his students.
As he sadistically slaps the child, the teacher yells, "Don’t joke around, kid! Do you understand? You’re stupid!"
The incident was recorded at a practice game in the Gifu area on Sunday by another student using a mobile phone.
According to the Japan Times, the teacher admitted the physical abuse of the second-year student, saying, "I wanted to shake him up, but I went about it the wrong way."
The victim has not been named, but was either 16 or 17.