Literally "brown hair", chapatsu (チャパツ) is the once-rebellious, once-trendy style of bleaching (and occasionally dyeing) hair, found among Japanese teens.
While the style itself began to show up in Tokyo streets during the early to mid-1990s, the word did not appear in Kōjien (one of Japan's authoritative dictionaries) until 1998. The style first gained popularity among adolescent girls, seeking to accentuate their tanned skin (rebelling against more traditional definitions of beauty), but quickly grew into the mainstream.
The latest trends seem to indicate that the "chapatsu" style is on its way out.[1]
Chapatsu came to be allowed as not only young people but also members of society according to the type of business, and it was established before long as one of the Japanese fashions.