There are many rules and regulations in judo, and the purpose of most of them is to protect the safety of the two competitors while on the judo mat. Here is a selection:

Players must not enter a contest wearing any jewellery, watches, body piercings or any other hard objects. Even hair ties will be checked by the referee to make sure there is nothing in them that could injure either the player or their opponent.

A player's judo suit must conform with regulations which, amongst other things, prohibit loose, unstitched fabric such as frayed badges or back patches. These may catch in their opponent's fingers or toes and cause injury.

The contest action must only take place within the designated contest area, usually outlined by a border of red mats. When players stray out of this area the play is stopped and the players are brought back to the centre of the mat to restart the contest.

Several methods of gripping the opponent's judo suit are forbidden because they pose an injury threat.

Armlocks and strangles are only allowed for players over the age of 16 years. In junior contests referees are always on the lookout for accidental strangles in ground work and will stop the contest if they see anything wrong.

A defending player may be penalised by adopting certain postures or stances which ar deemed to put himself or his opponent at risk. One axamples is attacking in a stooped posture with head bent; this can pose an injury risk to the player's head and neck.

The contest rules are constantly being updated to exclude harmful actions. Recent changes include prohibiting certain types of throws for young players as they were seen to pose unnecessary additional risks.