TOKYO - For some teachers in Japan, the most punishing part of the job does not happen in the classroom. It comes in the form of late-night phone calls, prolonged confrontations and relentless demands from so-called monster parents -- a growing problem that is pushing educators to the brink.

One holiday afternoon, the cell phone of a male teacher in his 20s living in the Kansai region rang. He supervises a school club, and the caller, the parent of one of his students, immediately launched into a tirade.

Related coverage: