Central Shibuya, one of the trendiest districts in Tokyo, is a magnet for young people. "It's exciting like New York," says an American junior high school student on home stay here. But it is also a dangerous place for naive teenagers, as illustrated by last week's kidnapping of four school girls.

According to police, the four elementary school students, aged 11 and 12, were lured by a young jobless man to his apartment, presumably with offers of money and part-time work. They were held captive there for four days, handcuffed and blindfolded. One of them managed to escape and seek help. The man, who was said to have a record of picking up young girls on Shibuya streets, is believed to have committed suicide.

Many lessons can be drawn from the incident. One is that many teenage students are defenseless against the dangers lurking in amusement quarters like Shibuya. So it was with the kidnapped girls, who appeared to harbor no suspicions about their would-be abductor. There seems to be an appalling lack of social maturity among today's teens.