Anyway, a Japanese middle school graduation is like an American high school graduation in that it marks the end of mandatory education, and high school, for those who choose to apply, is the first place you have to fight to get into. (Entrance exams are pretty brutal.) And a graduation here requires about two weeks of practices and preparations.
There was such a practice today. The assistant vice principal explained to everyone how to stand up, how to bow (at the moment that he says"bow" or else when someone on the stage bows to them, held to a count of two), and where to look. Then there was song practice, because they have to sing the school song and the graduation song.
It's hard to explain the atmosphere even at the practice-- super strict, super formal, happy and sad as graduations are, but with an undercurrent of highly repressed hilarity. It's just do formal that some people just end up laughing. Imagine a workshop where the instructor tells everyone to make their bodies into a square. Then imagine he tries to make everyone more square: "You, tuck your head in more! You, make your torso wider! You, make your butt more cornery!". Of course people would end up laughing.
Naturally, laughing is strictly prohibited at the graduation itself.