Judo Basics: Rules, Principles, and Terminology

Definition of Judo

Judo is a combat sport based on self-defense, in which each competitor uses their opponent's strength to project them onto the ground, immobilize them, or force them to give up the struggle through a joint lock or strangulation.

Two Fundamental Principles

• The Principle of Efficient Use of Energy: Judo movements performed correctly represent the minimal use of physical and mental energy. For example, most fighting techniques exploit the opponent's weight to unbalance or throw them.
• The Principle of Mutual Prosperity and Friendship: For Jigoro Kano, the harmonious development of human beings is only possible through the concessions granted by people themselves.

Fighting Area and Rules

Fighting takes place on a tatami. In the case of fighting between people with visual impairment, this area also has a lower resistance that causes the temperature to be different from the rest of the tatami.

• When a judoka is five seconds with both feet in the danger zone without any attack, they are sanctioned.
• And when a judoka leaves the tatami (safety zone) without performing any attack, they are also sanctioned.

Referees

• There is one referee whose position on the mat determines the scores and key actions of the match, and two chair umpires, who are seated in opposite corners of the mat outside the danger zone.
• Although the central referee bears the primary burden of leading the match, the chair umpires are equally important as they also score techniques and may even override the central referee's decisions to ensure their criteria are met.

Fight Duration

• It is five minutes of real time.
• They begin with a greeting with which the fighters agree to fight loyally and accept victory or defeat without disturbing the serenity of their spirit.

Frequently Used Terms

• Dojo: A place where Judo is practiced (minimum 9x9m, maximum 10x10m).
• Hajime: Referee's command to start the match.
• Sore-made: Referee's command to end the match.
• Judoka: A Judo practitioner.
• Judogi: Judo uniform.
• Osaekomi: Indicates the start of an immobilization.
• Toketa: Referee's command to indicate that the judoka has escaped from an immobilization.
• Matte: Referee's command to temporarily stop the match (e.g., to fix the judogi, for misconduct, or injury).
• Rei: Greeting/bow.
• Ippon: A technique or score representing 10 points and immediate victory.
• Waza-ari: A score equivalent to 7 points. Two waza-ari equal one ippon.
• Yuko: A score equivalent to 5 points.
• Koka: A score equivalent to 3 points.