There are seven weight classes for men and women, with bouts lasting five minutes for men and four for women. The maximum weights are:

Extra lightweight: 60kg, men; 48kg women
Half lightweight: 66kg men; 52kg women
Lightweight: 73kg men; 57kg women
Half middleweight: 81kg men; 63kg women
Middleweight: 90kg men, 70kg women
Half heavyweight: 100kg men; 78kg women
Heavyweight: over 100kg men; over 78kg women

A draw divides the "Judoka", contestants, into two pools, which proceed in a single elimination tournament that ends with gold, silver and two bronze medals being awarded.

There is no knockout in judo, rather the aim is to subdue opponents with technique and controlled power in a way that throws the opponent off balance and allows them to be thrown. A throw of the right kind wins a bout outright, making for a swift result.

Bouts are fought on tatami, covered mats two metres long and a metre wide that form a 14 metres competition area. The green contest area at the centre is a six metres square, surrounded by a one metre red alert area, which in turn gives way to an outside, or safety, zone which is three metres wide. Strips of white and blue tape in the contest area mark the point at which the contestants start their bout.

Judoka wear judogi, pants and jacket with a black belt to signify their status. One judoka wears a blue judogi, the other wears a white one.

The scoring of bouts is as follows:

Ippon: where a judoka scores one point. Judoka can win the bout with a throw that immobilises an opponent in a hold for 25 seconds. Submission brings the same result. To score an ippon with a throw, the throw must meet four criteria; the opponent must be thrown mainly onto his or her back, and the throw must be controlled, forceful and rapid.

Waza-ari: two half points are awarded when one of the four criteria for an ippon with throw has not been met. Similarly, a waza-ari is awarded if the hold lasts for 20 seconds, not 25.

Yuko and Koka: these do not result in points. A yuko is awarded if two elements of a throw are missing or a hold lasts between 15 and 19 seconds. A koka is awarded if three elements of a throw are missing or if a hold lasts between ten and 14 seconds. Yuko and koka can be awarded to one opponent as a penalty to the other opponent for rule infringements. A tally of yuko and koka is kept to break a tie. If then a tie cannot be broken, the judge decides.