In the Paralympic Games, Judo is practiced by people with visual impairments. High-performance competitions began during the 70s. However, Judo did not make its debut before Seoul 1988 Games, in South Korea, with the participation of male athletes.
Women have been participating since the Athens 2004 Games. The entity in charge of the sport is the International Blind Sport Federation (IBSA), founded in Paris in 1981, and the rules are set by the International Judo Federation (IJF).
Paralympic Judo’s classification system is based on medical criteria rather than functional, as in most Paralympic sports.
Athletes are divided into different categories identified by letter B (for Blind): B1 for the totally blind, B2 for players who can perceive light and shadow, and B3 for participants who can detect images. They can fight each other, but there are also weight categories, which follow the Olympic standard.
Besides the classification based on the degree of visual impairment, Paralympic judo has some special features, such as speaking the words ao and shiro (Japanese for blue and white, respectively), immediately after announcing the scores and penalties, and the start of combat is authorised by the referee only when the athletes are gripping the opponent’s kimono.
Another function of the referee only performed in Paralympic judo - and perhaps the most important - is to ensure constant contact between participants; i.e. they must be in contact with each other throughout the fight. If contact is lost, the fight is stopped. B1 athletes are identified by a red circle located on the sleeves of their kimonos, so that the referee knows that he must put them in contact with each other before restarting the combat.
As in the Olympic competition, fights take place on synthetic mats and each match lasts up to five minutes for the men and up to four minutes for the women. Competitors strive for the ippon (the "knockout" of judo) by throwing the opponent onto his back, immobilising him on the ground and finishing with an arm lock or stranglehold.