Gyoji are referees in the sport of sumo, responsible for officiating matches and ensuring that the rules are followed. They wear traditional attire, including a black kimono and a distinctive hachimaki headband, and are known for their ceremonial role in the ring. During a match, the gyoji signals the start and end of the bout, and they also make decisions on the outcome. Their authority is respected, and they play a crucial role in maintaining the integrity of the sport. Gyoji are trained in the traditions and techniques of sumo, making them essential figures in this ancient Japanese sport.