A Japanese government panel on education reform has called on schools to tackle classroom bullying, after a recent spate of student suicides.
The education minister has welcomed the proposals
The Education Rebuilding Council urged school chiefs to warn children about the dangers of bullying and to teach them not to turn a blind eye.
Teachers who encourage or fail to stop bullying should be punished, it said.
Bullying has long been a problem in Japan, but five recent suicides linked to it have re-stoked concern.
Anonymous letters claiming to be from suicidal children have also been received by the Education Ministry in recent weeks.
"Bullying is an anti-social act that should not be tolerated," the Education Rebuilding Council wrote in a report submitted to Prime Minister Shinzo Abe.
"We need clear standards for guidance and punishment."
The panel also calls for closer cooperation with teachers, parents, community groups and experts to tackle the problem.
The proposals have been welcomed by Education Minister Bunmei Ibuki as a way to "raise awareness of the bullying problem".
Bullying and related suicides are not a new problem in a country where children are under intense pressure to conform.