Judo, a martial art and combat sport originating in Japan, has been around for over a century. Initially, judokas wore traditional white gi uniforms that symbolized their status as students of the martial art. However, over time, the judo community began to adopt blue gis as part of its uniform system.

The main secret behind this change lies in the perceived psychological effects it had on athletes. Blue is often associated with feelings of trust, loyalty, and strength - qualities that are highly valued in a martial art like judo.

Research suggests that wearing blue gis can also enhance an athlete's performance and mental state by promoting relaxation, reducing anxiety, and increasing focus. This phenomenon is often referred to as the "blue aura."