In professional sumo wrestling, five ringside judges officiate each bout alongside the referee.
These judges are called shimpan. They sit around the dohyo, or raised sumo ring, and watch the contest closely. Their most visible role comes when a bout ends too quickly or the referee’s decision appears questionable.
A judge can call for a mono-ii, a conference in which the ringside judges review what happened. They may uphold the referee’s ruling, reverse it, or order a rematch. The judges also help determine whether a wrestler stepped outside the ring or touched the ground with a body part other than the soles of the feet.
The five judges are separate from the gyōji, the traditionally dressed referee inside the ring. Confusing these roles is common: the gyōji announces and initially judges the result, while the shimpan provide ringside oversight. Senior officials may also review bouts from a larger judging committee when necessary.