The tragic death of a 17-year-old Osaka high school student and basketball captain in December sheds light on a disturbing aspect of Japanese culture that has existed for decades: corporal punishment.

It's not a secret; most Japanese know about it, experienced the humiliation associated with it, witnessed others' humiliation, or chose to ignore it. Or felt it was impossible to change, felt powerless to do so.

In Japan, there's an unwritten rule that permits coaches and sporting mentors to slap, kick and punch players to get them to "toughen up."