According to the school, the teacher has admitted to the abuse, saying: "I wanted to shake him up, but I went about it the wrong way."
"Don't joke around, kid! Do you understand? You're stupid," the teacher is heard yelling in the video as he repeatedly slaps the student's face, according to Agence France-Presse.
The assistant principal of Hamamatsu Nittai Senior High School told the AFP the teacher had also beaten another student on the same day.
Michael Rusch is a socials editor for BuzzFeed News and is based in New York. Rusch was selected by Time as having one of the 140 Best Twitter Feeds of 2013.
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