Kogal (also known as Kogyaru) is one of the many substyles of Gyaru fashion. This style revolves around younger girls and usually young girls in highschool. It is also the originator of several modern gyaru styles.
The style itself is based around school uniforms. Any type of school uniform is fine, although most uniforms tend to have checkered skirts, bows around the neck and sweaters.
There is then things that add a gyaru twist to the uniform, such as short skirts, bunched up tube socks or legwarmers.
The style is also characterized by dyed hair, and with older girls, tanned skin. Tanned skin has become less common in kogal, however, as tanning itself has become less popular among gyarus.
Originally, kogal had a very negative reputation, being seen as fashion for delinquents, but in modern times the Kogal style has gained much more popularity. It is now a well-liked in Japan, and internationally as a kawaii fashion style.