Basic Rules

Judo competitions are held in accordance with the Kodokan Judo Competition Judging Regulations. Information regarding the contest area, the technique (waza) judgments, and win judgments is given below.

Contest area

Competition area

  • The official contest area is a 14.55m x 14.55m square, with a 9.1m x 9.1m square area in its center.
  • Tatami mats (2.73m wide) are placed around the contest area's outer perimeter.
  • The contest area boundary is marked by a red line (square) approximately 90cm in width.
  • Two short lines of tape mark the positions in the center of the contest area where the two contestants stand to perform their "rei" (bows). The two lines are approx. 5cm wide, 30cm. long, and are approx. 3.64m apart. One of the lines is red, and the other is white. Viewed from the front, the red line is on the right, and the white line is on the left.

Technique (waza) judgments

[Nage waza] (Throwing techniques)
When a contestant applying a technique, or countering his opponent's attacking technique, throws down his opponent onto his back with sufficient force.
[Katame waza] (Grappling technique)
When the opponent says "maitta" ("I give up"), or taps his or his opponents body or the mat two or more times with his hand or foot.
[Osae waza] (Hold-down technique)
When contestant fails to break free within 30 seconds from a hold being applied by the opponent.
[Shime waza and kansetsu waza] (Strangling and joint lock techniques)
When the effect of the technique is sufficiently apparent. Triangle strangles and joint locks are forbidden in competitions involving junior high school and younger contestants, and joint locks are forbidden in competitions involving primary school and younger contestants.

Two "waza-ari" result in an "ippon gachi" (Win by ippon).

[Nage waza] (Throwing techniques)
When a contestant throws his opponent in good form, but not quite to the degree which merits an "Ippon".
[Katame waza] (Grappling technique)
When a period of 25 seconds or longer elapses.

Regardless of how many Yukos are received, they will never result in a "Waza ari" or an "ippon gachi".

[Nage waza] (Throwing techniques)
When a waza occurs which falls just short of a "Waza ari".
[Katame waza]
When a period of 20 seconds or longer elapses.

Win judgments

The contestant who receives an "ippon gachi (Win by ippon)" wins the contest.
[Yusei gachi]
The winner is determined by the judges. This occurs when a contest ends without a clear winner.
[Other judgments]
"Win by default" (non-appearance of opponent), "Win by default" (opponent withdraws during the contest), "Win by opponent's disqualification".