The Japanese city of Kobe, hit two years ago by a devastating earthquake, has now been shaken by news of the arrest of a 14-year-old for murdering and beheading an 11-year-old acquaintance because of a grudge against his school.

Police arrested the boy one month after the discovery of Jun Hase’s severed head at the gateway to the accused’s middle school in Suma ward, Kobe. The killer had placed a note inside the dead boy’s mouth, which read: “Now the game begins. Stupid cops, try and stop me. I can’t help but enjoy killing. I want nothing more than to see someone die ... Shooll (sic) Killer, Sakakibara Seito.”

The arrested boy, who was a neighbour of the victim, confessed to killing Hase and abandoning his body, police said. Investigators searched the suspect’s home where they found a knife believed to have been used to decapitate Hase.

The particularly gruesome murder, and the revelation that the accused killer’s long-standing grudge is against Japan’s authoritarian education system, has caused much soul searching in Japan. A second note sent to a local newspaper by the murderer explained that the slaughter of Hase was to avenge grievances he held against the school system. The rambling note also warned he would kill again.

Since the boy’s arrest and alleged self-confession to the murder, police say he has also confessed to two separate attacks on two local schoolgirls, Ayaka Yamashita, 10, and Hitomi Horikawa, 9, on March 16. Ayaka died of head wounds after being attacked with an iron bar.

The boy is said to come from an ordinary middle-class background and his father worked for a respected company.

The arrest has highlighted violence by Japanese youngsters and increased concern that the level of violence at schools is rising to unheard-of levels. The Japanese education ministry has said that the reported number of violent junior- and senior-high schools incidents has tripled over the past decade from 2,801 in the 1986 school year to 8,031 in 1995.

The incidents include violent behaviour toward teachers, students and destruction of school property. The rise in violence by youngsters and the Jun Hase murder case has brought calls for a change to Japan’s criminal law for juveniles, which states that criminal charges cannot be brought against those under 16.

The juvenile law also stipulates that the suspect cannot be named, nor can any of his other personal details be published. However, one Japanese magazine, Focus, has flaunted the law by printing a picture of the arrested child along with details of his home and parents - a practice common in the media treatment of adult criminal suspects in Japan.

Japan’s biggest selling newspaper, the Yomiuri, has called for “far-reaching debate and improvements in the school system, government programmes for the young and the educational roles of the family and society”.

Nobuto Hosaka, a democrat socialist MP, said: “We need to recognise that the stress levels of our youngsters is reaching a dangerous level so our first task is to alleviate all this accumulated pressure.”

A common feature of the media comment has been reference to the particularly grisly comics and computer games available to Japan’s young. Yomiuri questions the “unlimited access to information” in Japanese society.

Where there has been comment, inevitably violent comics, TV, videos and computer games have been singled out for criticism. Too many children are living in a fantasy world, say critics of the entertainment industry.

Many fear an increasingly street-wise “Nintendo generation” is growing up in a rapidly changing Japan which had long been proud of its safe streets. Now, since the Hase murder arrest, many parents around Kobe are still afraid to send their children to school in the traditional way - on foot.

Children living near the scene of the murder are now taken to school in groups with a guardian adult. Schools in the area are also providing counselling for perturbed students and parents.