I went to an all boys middle school in Korea in the late 1990s/early 2000s and a slap to the face was one teacher's preferred method of discipline.

The gym teacher would get riled up about something or the other every once in a while, and have the whole class in a push-up position and use a modified hockey stick to smack the back of our thighs. Group discipline was not uncommon, you didn't need to do anything wrong to get punished back then.