A student pulls the hair of another student in an undated file photo.Cases of violence by Japanese school students hit a record high in the past year, with elementary students increasingly violent, the education ministry said.

Cases of violence by Japanese school students hit a record high in the past year, with elementary students increasingly violent, the education ministry said.

The number of cases jumped 18 percent to nearly 53,000, which some experts have linked to increasing stress among children pushed to excel in their studies and also join a raft of extracurricular activities.

"We heard from school boards that children cannot control their emotions and there is a decline in their moral values as well as the lack of their ability to communicate well," an education ministry official said.

The number of cases involving elementary school children, both at school and elsewhere, jumped 37 percent to 5,214 incidents in the year to March 2008.

However, there were fewer cases of bullying by students, which the ministry counts separately, although it added that the 101,000 cases found at Japan's 40,000 schools was still high.

Bullying at schools, ranging from bantering and bashing, ignoring and shutting out from student groups to beating and kicking has long been a problem in Japan.

Technology comes into play, with cases of bullying emails through mobile phones rose by 1,000 cases to nearly 5,900 incidents in the past year.

"Students do not want to leave any evidence of bullying, so online bullying is still not the main problem," Kenjiro Kubo, who heads a non-profit group that helps bullied students.

 校園