General Information
Aikido competition takes place on a mat at least 9 meters (about 29 feet) square, surrounded by a safety area.
There are four types of competition: Kata, Ninin Dori, Tanto Randori, and Randori Kyoghi.
For the first two, there are a least three judges, including a senior judge, outside the competition area. For the last two, a referee works inside the combat area and there are two judges outside.
In important competitions, there are two other officials, a timekeeper and a recorder, who keeps track of scoring.
Contestants wear jackets and trousers, as in judo. One wears a white belt, the other a red belt.
Kata
This is a non-combat conpetition in which two contestants perform a kata, a predetermined sequence of moves, within a time limit of 2 to 3 minutes. The kata has to be announced to the judges in advance. If it's probable that the judges don't know the kata, they must be given a written sequence of techniques.
One contestant is Uke, the attacker, the other is Tori, the defender. Judges score the team, from 0 to 10, on the basis of balance, positioning, correct performance, finishing technique, and how well they coordinate their moves.
Ninin Dori
Three contestants work together as a team for a total of 1 1/2 minutes. Each is the defender (Tori) for 30 seconds, while the other two are attackers. After the time is up, one of the attackers becomes the defender for the next 30 seconds; then the third member of the team assumes the role of defender.
Scoring is essentially the same as in kata, but use of the entire competition area is also one of the criteria.
Tanto Randori
This competition involves free fighting between two opponents for two rounds of two minutes each. One competitor has a rubber knife, the tanto, for the first round.
The competitor with the red belt starts the first round as the attacker, armed with a rubber knife. They begin at the center of the mat, 4 meters apart.
The attacker can score by striking the defender anywhere between the belt and the shoulder line, in front or back, provided that the attack begins from the hip line, is made with a thrusting movement after both feet have moved forward, and ends with the attacking arm fully extended and the knife in the horizontal position.
The defender can score with any skillful aikido technique. One point is awarded for avoiding attack with a correct basic technique, or if the attacker is thrown out of the area while the defender has remained in the area throughout the action.
A half-point is awarded if the defender makes a successful sacrifice technique or breaks the opponents balance and has control with an aikido lock without putting the attacker is not put on the ground.
If either competitor scores a point, the knife changes hands and they reverse roles. After the first two-minute round, the second round begins immediately with the white-belted competitor as the attacker.
The match ends immediately if a competitor scores a total of two points. After two rounds, the competitor with higher score wins. If the score is tied after two rounds, a two-minute extension period takes place. And, if the extension period doesn't decide the contest, the judges decide the winner, based on skill and technique.
Randori Kyoghi
This is free fighting between two unarmed contestants for one three-minute round. As in tanto randori, the match ends as soon as a contest has totalled two points.
There is no extension period in randori kyoghi. If the score is tied when the three-minute round ends, the winner is the competitor who attempted the most techniques with the proper style, in the opinion of the judges.
Fouls
These are fouls in both forms of randori:
Unsportsmanlike, dangerous, or non-aikido behaviour or techniques; holding the opponent's clothing, grappling, or preventing actions in any way; repeatedly stepping outside the area or forcing an opponent outside the area.
In tanto randori, using an incorrect attack with the knife is also a foul.
Fouls may be punished by a half-point deduction, a simple warning, or disqualification.