Illegal techniques in judo fit on a short, precise list. You may not grab the legs in standing, and you may not lock any joint except the elbow. Kawazu-gake and kani-basami are banned outright. Diving head first and striking are forbidden too. Depending on how serious the act is, the referee gives a shido or a direct hansoku-make. Young judoka have extra restrictions on top.
Almost every one of these rules was written after people got hurt. They exist to protect your joints, your neck and your head.
Illegal moves that earn a shido
Grips below the belt are the most common case. In standing, you may not:
- grab the legs or the trousers to throw;
- hook a leg with your hand or arm, at any height;
- touch the legs below the groin;
- grip the inside of the trousers.
Since 2025, the IJF does allow gripping the jacket below the belt and the trousers up to the groin, as long as you use the grip to attack. A leg grab is still legal in one situation: at the end of a throw, to follow up on the ground.
These bans pushed some throws out of competition judo. The classic kata-guruma with a leg grab is gone, and so is morote-gari. Judo chose to separate itself from wrestling, and that choice fits its identity. We compare the two sports in judo vs wrestling.
Other actions punished by shido:
- hugging the opponent's trunk with joined hands without attacking;
- putting a hand or foot directly on the opponent's face;
- applying a lock or choke in standing without a throw, when the risk is low and the opponent can escape.
Behavior fouls such as passivity or false attacks are covered on our page about shido penalties in judo.
What gets you a direct hansoku-make
The banned techniques
IJF rules give hansoku-make for four techniques that the Kodokan classifies but forbids in competition.
| Technique | What it does | Why it is banned |
|---|---|---|
| Kawazu-gake (one-leg entanglement) | Leg wrapped around uke's leg, fall backward | Twisted knee and ankle, both players land on uke |
| Kani-basami (crab scissors) | Scissor of the legs at the waist, uke falls backward | Serious knee injuries |
| Do-jime (trunk strangle) | Squeezing the trunk or kidneys between the legs | Risk to ribs and internal organs |
| Ashi-garami (leg entanglement) | Leg lock by wrapping the leg on the ground | Knee damage |
Older judoka still talk about kani-basami with real unease. Kawazu-gake and kani-basami remain described by the Kodokan, but on the list of prohibited techniques. You can discuss them in the dojo. You never try them in randori.
Dangerous locks and chokes
In judo, the elbow is the only joint you may attack with a lock. Twisting a wrist, shoulder, knee or ankle is illegal. An armlock or choke applied while throwing, when uke cannot escape and risks a serious injury, earns hansoku-make. Since 2026, ushiro-sankaku on the ground is punished the same way when it puts uke's neck at risk.
Legal locks such as juji-gatame are covered in our guide to katame-waza. Brazilian jiu-jitsu allows more submissions depending on belt level, as our article on IBJJF rules and points explains.
Diving head first
Diving head first into the mat while throwing, bending the neck forward or backward, is illegal at every age. It happens mostly on uchi-mata, harai-goshi and seoi-nage when a player tries to finish at any cost. A forward somersault with the opponent on your back is treated the same way. What this penalty means for the rest of the tournament is explained in our page on hansoku-make in judo.
Acts against the spirit of judo
Punching, kicking, any deliberate attempt to injure, insults: hansoku-make and removal from the event. Deliberately putting an opponent in danger also belongs here, for example letting them land on their head.
Extra bans for young judoka
At cadet level and below, the IJF gives a shido for three actions that remain legal for juniors and seniors: using the head to throw, using the head to defend while turning, and the reverse seoi-nage.
National federations add their own age-based limits. Armlocks and chokes are usually forbidden for the youngest players and are introduced step by step through the age groups. Some sacrifice throws or risky techniques can also be restricted. The details change by country, season and level, so the rulebook for your category is the reference. Age groups are explained in judo age categories.
The full framework is in our guide to judo rules.
A coach's take on the list
The list looks long. It is easy to learn once you connect it to one idea: judo protects every joint except the elbow, plus the neck and the head. In training, correct leg grabs the moment they appear, even in games. A habit built in randori always comes back in competition, at the worst moment. If you also train BJJ, take a minute before each tournament to switch your head to the right rulebook.