The Wrist Lock (mão de vaca) is a joint lock that forces the opponent’s hand into hyperflexion against the inner forearm, attacking the small wrist joint to force a fast tap; it is most accessible from closed guard top against an opponent’s posting, planted hands.
Safety
Wrist Lock targets the Wrist and carpal joint. Primary risk: Wrist sprain or ligament tear from hyperflexion. Tap early; release immediately on the tap. Full safety guide ↓
The Wrist Lock, known in Portuguese as mão de vaca (‘cow’s hand’) and in judo as a tekubi joint lock, is one of the most accessible and universally legal joint locks in Brazilian Jiu-Jitsu, available to every belt from white up under IBJJF rules. The standard flexion version forces the opponent’s hand toward the inside of their own forearm — bending the palm down toward the wrist crease — until the small carpal joint reaches its end range and the opponent taps. From closed guard with you on the bottom, the lock is most often hunted against a posturing opponent who plants a hand on your chest, hip, or the mat to control your guard; that planted, straight-armed hand is exactly the lever the wrist lock attacks. By pinning the opponent’s palm flat against your sternum or a controlled surface and then curling their fingers and palm toward their forearm, you load the wrist with very little movement and almost no telegraphing. The wrist lock is prized precisely because it punishes good posture and strong grips: the harder an opponent posts and pushes, the straighter their wrist becomes and the shorter the path to the finish. It chains naturally with collar grips, the Kimura and Americana families, and overhook control, and it serves both as a primary finish and as a way to break grips and open a stubborn defender’s hands.
Starting Position: Closed Guard · From: Closed Guard (Bottom)
Outcomes
| Result | Position | Probability |
|---|---|---|
| Success | game-over | 42% |
| Failure | Closed Guard | 40% |
| Counter | Closed Guard | 18% |
Attacker vs Defender
| Attacker | Defender | |
|---|---|---|
| Focus | Execute and finish | Escape and survive |
| Key Principles | The wrist lock is flexion: bend the opponent’s palm toward t… | The wrist lock dies when the elbow bends — pulling your elbo… |
| Options | 7 execution steps | 3 defensive options |
Playing as Attacker
Key Principles
-
The wrist lock is flexion: bend the opponent’s palm toward the inside of their forearm, not away from it
-
Trap the palm flat against a solid base — your sternum, hip, or the mat — so it cannot escape the pressure
-
Control the elbow line; if the elbow can travel, the opponent escapes by bending the arm and the lock dies
-
Use minimal motion and your whole body, not just your hands, to fold the wrist
-
A posting, stiff-armed opponent pre-loads their own wrist — let their pressure shorten your finish
-
Keep the opponent’s fingers and palm together; a splayed hand can sometimes slip the angle
-
Apply slowly and progressively because the joint has almost no margin before injury
Execution Steps
-
Identify the planted or gripping hand: Spot the opponent’s straight posting hand on your chest, hip, or the mat, or a defensive grip on you…
-
Pin the palm flat to a base: Cup or clamp the opponent’s hand and press the palm flat against a solid surface such as your sternu…
-
Control the elbow line: Trap or frame against the opponent’s elbow so their arm cannot bend or rotate to follow the wrist, e…
-
Begin the flexion fold: Drive the opponent’s fingertips and palm down toward the inside of their forearm, folding the wrist …
-
Add body weight or rotation: Use your chest, hips, or a slight rotation of your torso to drive the fold rather than relying on ha…
-
Close the angle to end range: Continue the flexion smoothly until the opponent’s wrist reaches its end range, keeping the elbow tr…
-
Finish and release on the tap: Apply the final increment of flexion over a couple of seconds and release the instant the opponent t…
Common Mistakes
-
Bending the wrist in extension instead of flexion
- Consequence: You attack the wrong direction, the opponent simply resists, and the lock generates no real pressure
- Correction: Fold the palm toward the inside of the forearm; the standard mão de vaca is a flexion lock, not extension
-
Letting the opponent’s elbow travel or bend
- Consequence: The arm follows the wrist, the pressure dissipates into the shoulder and elbow, and the finish disappears
- Correction: Trap or frame the elbow line first so every degree of fold loads the wrist joint itself
-
Relying on hand and finger strength alone
- Consequence: A strong opponent out-muscles your grip, you fatigue, and the wrist never reaches end range
- Correction: Pin the palm to a solid base and drive the fold with chest, hips, or torso rotation instead of just your hands
Playing as Defender
Key Principles
-
The wrist lock dies when the elbow bends — pulling your elbow toward your body unloads the joint
-
Never leave a stiff, straight, planted hand exposed for the opponent to pin and fold
-
Recognize the flexion attack early; the wrist has almost no range before injury
-
Keep your hands and fingers active and moving rather than posting rigidly
-
Free the trapped hand by retracting the whole arm, not by fighting just the wrist
-
If your hand is genuinely pinned and the fold is sealed, tap early rather than risk the joint
-
Avoid feeding posting pressure into a hand the opponent has already begun to trap
Recognition Cues
-
The opponent traps and pins your posting or gripping hand flat against their chest or the mat
-
You feel your palm being folded down toward the inside of your own forearm
-
Your elbow is being framed or trapped so your arm cannot bend away
-
Sharp, localized pressure building in the wrist rather than the elbow or shoulder
Escape Paths
-
Bend the elbow and pull the whole arm back to recover a free, mobile hand
-
Posture and drive forward to pass and remove the opponent’s attacking angle
-
Tap early and reset if the wrist is genuinely sealed at end range
From Which Positions?
Safety Guide
Injury Risks:
| Injury | Severity | Recovery Time |
|---|---|---|
| Wrist sprain or ligament tear from hyperflexion | Medium | 2-6 weeks depending on ligament damage |
| Carpal joint or scaphoid injury from sudden force | High | 6-12 weeks, longer if a fracture occurs |
| Finger or hand strain from gripping resistance | Low | 1-3 days |
Application Speed: SLOW and progressive - the wrist has a very short range before injury, so apply over 2-3 seconds and stop the instant resistance ends
Tap Signals:
- Physical hand or arm tap with the free hand
- Foot tap on the mat
- Verbal tap
- The trapped hand going limp or stopping its resistance
- Any wince or sharp distress signal as the wrist reaches end range
Release Protocol:
- Release the flexion pressure on the wrist immediately and completely
- Let the opponent’s hand and forearm return to a neutral straight position
- Do not jerk the hand back open — allow it to relax naturally
- Check the partner’s wrist and hand for any sign of injury
- Confirm the partner can move the wrist through normal range before continuing
Training Restrictions:
- Never apply the wrist lock with a jerk or snap — the joint has almost no margin
- Always apply slowly and progressively, releasing the moment the partner taps
- Never crank past the tap; small-joint locks injure with very little extra force