Staff writer

One evening recently, Ryuhei Mizumoto was examining dozens of knives in a glass display case in a shop in Tokyo's Shinjuku Ward.

"I like looking at knives," said the 19-year-old public servant, clad in a light-blue jacket and wool cap. "I think they're kind of beautiful." A comment like Mizumoto's may seem innocuous enough, but for many people, knives have recently taken on a disturbing allure -- they are the perfect weapon for teenagers.