Watashitachi no Kyokasho (2007)

Plot twists in this drama are what will keep your attention. The writer did an excellent job accomplishing the arousal of the horror of group bullying in schools where children are basically imprisoned all day. It also draws attention to the importance of teachers protecting their students.
What kept this drama from getting a higher rating was overkill by the writer. There were too many victims. In addition, the vice principal's psychotic son was not necessary to the plot and totally detracted from the climax and well written ending.