The Two Types of Judo Uniform — White and Blue
A judogi (judo uniform) consists of a joi (top), shitabaki (pants), and an obi (belt). One competitor wears a white uniform, the other wears blue. Traditionally, both competitors wore white, but in 1997 the International Judo Federation officially decided to use blue judogi.
This coloring makes it easier for spectators to distinguish the competitors. It also makes it easy to distinguish competitors during katame-waza (grappling techniques). Blue judo uniforms were first used at the 2000 Sydney Olympics and colored judo uniforms have become the standard at the World Championships and other major tournaments.