Bullying has long been an issue in Japanese schools, which already had a reputation for being stricter and more regimented than schools in Europe, but authorities here are having to cope with a sudden increase in cases - some so severe that they have been blamed for endangering the lives of the children involved.

In the most extreme cases, bullying is also the cause of suicide amongst Japanese youth.

On November 9, the Komatsu branch of the Kanazawa District Court, north of Tokyo, awarded the family of a 12-year-old girl 7.03 million yen (69,051 euros) in damages after she developed post-traumatic stress disorder (PTSD) which the court deemed a result of abuse from her classmates.

The family, whose name has not been made public as the girl is a minor, had sought 48 million yen in damages from the parents of nine other children at the school and the city of Kaga for failing to intervene.

"The bullying of the three classmates caused the development of PTSD and the city was lax in its duty to protect the child," Judge Akira Onose said in his ruling.

Name-calling progressed to the girl being pushed down a staircase. The school had been made aware of the problem, the judge said, but teachers had been slow to contact the parents of the other children allegedly involved. Onose ruled that the bullying "inflicted unbearable emotional pain and was illegal."

75,000 cases in six months

The case, while shocking among pre-teen children, is far from unusual in Japan.

The education ministry conducted what it described as an "emergency survey" on the problem in the nation's schools and released a report on October 1. The report identified an estimated 75,000 bullying cases in schools in the previous six months. That figure was a steep increase from the 70,231 incidents reported in the entire 2011 school year.

And while bullying has been around for generations, today the chosen method of persecuting an individual has morphed into "cyber-bullying," with personal attacks increasingly made via the Internet. Most worrying, the ministry concluded, was that 250 cases were so severe that the "child's life or physical well-being were at risk."

The report was ordered in the aftermath of an incident that shook public faith in the education system and the authorities' willingness to face up to the challenges of bullying.

In October of last year, a 13-year-old boy climbed to the top of a 14-storey apartment block in the town of Otsu, in central Japan, and leapt to his death on the concrete pavement below.

It took 10 months before authorities gave in to his parents' demand that an independent investigative committee be set up to look into the death. But in the months after the family spoke out, the case triggered a nationwide debate about bullying in Japanese schools and the devastating impact it can have on young people.

And because the school and police initially refused to accept there was any link between the boy's death and a pattern of long-running bullying, it put teachers, local education authorities and the police under the spotlight for failing to prevent cases of bullying.

Public anger at authorities

Such was the public anger at the failure of the authorities to act quickly that the head of the education board in the city was attacked with a hammer by a 19-year-old student. The suspect told police that he had intended to kill Kenji Sawamura for trying to conceal the truth in the case.

In a complaint filed with local police, the father of the boy who committed suicide listed the bullying that his son endured, which included being burnt with cigarettes, forced to shoplift, the destruction of his school books and being forced to practice committing suicide.

Lawyers representing the three boys named in the complaint have played down the severity of their clients' blame, saying in a written statement released to the media, "It was not bullying. It was a prank."

The boy, who has also not been named, is not an isolated case; during the 2011 school year, 200 students at junior and senior high schools committed suicide - an increase of 44 on the previous year and an all-time high since comparable data was first made available in 2006. Across all age groups, there were 30,513 suicides in Japan in 2011.

In August, the national government announced a new raft of measures designed to combat suicide among young people, requiring local education authorities, schools and families to share information on bullying and to swiftly deal with cases they identify.