What is knee reaping, and which leg locks are legal in jiu-jitsu?
A · Advanced · Submissions, fouls and referees · 1 of 3Straight ankle locks, straight knee bars and toe holds are legal from the under-18 group upwards. Locks that twist the knee or load it sideways, such as heel hooks, are legal only in no-gi matches for under-21s and adults. Knee reaping, crossing a leg over the trapped leg past the middle of the body, follows the same line.
How it works
- Straight ankle lock: legal from under 18.
- Straight knee bar: legal from under 18, if the force follows the knee's natural line and not sideways.
- Toe hold and other inward-turning ankle locks: legal from under 18.
- Heel hooks and other twisting or sideways knee locks: legal only in no-gi for under 21 and adults. Elsewhere, disqualification.
- Outward-turning ankle locks: treated as twisting the knee, with the same limits.
- Full reap: the attacker's leg crosses beyond the middle of the defender's torso with the foot trapped. Disqualification, except in adult no-gi.
- Partial reap with a submission on that leg: disqualification, except in adult no-gi.
- Partial reap without a submission: a minor foul. The referee moves the leg, gives a penalty and restarts.
- Foot outside the midline: legal.
- Accidental crossing on standing up: the attacker must remove it, or be disqualified.
The glossary has the knee reaping, the legal submissions (ne-waza), the prohibited acts by division, the major fouls (ne-waza), the minor fouls (ne-waza) and the gi and no gi.
Tricky cases
A heel hook in a gi match for adults. Legal?
No. Locks that twist the knee are allowed only in no-gi for the under-21 and adult groups.
An attacker's foot is in front of the defender's midline but no lock is being attempted. What happens?
A penalty, not a disqualification. The referee moves the leg to a legal position, gives the penalty and resumes.
The defender stands up and the attacker's leg ends up across the midline by accident. Who must fix it?
The attacker. The athlete applying the entanglement must remove the illegal position or be disqualified. For under 16 and younger, the position is reset to open guard with no foul.
A knee bar applied sideways in an under-18 match. Legal?
No. A straight knee bar is legal only when the force runs with the knee's natural straightening, not sideways.
Why the rule exists
A reaped knee is trapped at an angle at which a twisting force can tear its ligaments before the athlete can tap. The rule separates the straight locks, which hurt before they harm, from the twisting ones, which can harm first. Allowing the twisting ones only in adult no-gi keeps them for experienced athletes, where grips and the cloth do not slow an escape.
Where it differs
| Where | What changes | Source |
|---|---|---|
| Straight locks | From under 18 | JJIF Ne-Waza 10.1 |
| Twisting knee locks | Adult and under-21 no-gi only | JJIF Ne-Waza 10.1; 11.3.9 |
| Full reap or partial reap with a submission | Disqualification, except adult no-gi | JJIF Ne-Waza 11.3.10 |
| Partial reap without a submission | Minor foul | JJIF Ne-Waza 11.1.23 |
| Under 16 and younger, accidental reap | Reset to open guard, no foul | JJIF Ne-Waza knee reap guide |
From the rule book
Ju-Jitsu International Federation and Ju-Jitsu Asian Union, Jiu-Jitsu (Ne-Waza) Rulebook (version 2.7, reviewed 2024), Sections 10.1, 11.1.23, 11.3.9 and 11.3.10 and the knee reap guides. Checked 14 October 2026. Official document: the federation's Jiu-Jitsu (Ne-Waza) Rulebook.