Knee Cut Pass

Overview

The knee cut is the most reliable pressure pass in modern BJJ, used at every level from blue belt to black belt and across every ruleset. The pass starts from a half-headquarters position with one of your knees cutting across the opponent's top thigh while you control their far-side collar or shoulder and pin their near-side hip with your bottom shin. The cut itself is a small motion — six to ten inches — that slides your knee across their thigh to land your shin between their legs and your chest on their far shoulder. From there the pass to side control is automatic if the grips, the cross-face, and the underhook are correct. The reason the knee cut wins so often is that it converts the opponent's natural guard-retention chain into a back-take threat: if they shrimp away, you take the back; if they hold the underhook, you cut to side; if they hand-fight, you collapse the cross-face. The knee cut is also the pass that mmaGPT flags most accurately on video because every error is geometric and visible.

When to use it

Use the knee cut from any half-headquarters position where you have an underhook on the bottom player and they have a knee shield. It is the default pass against a knee-shield half guard, an open-guard player who has lost their hooks, and any retention sequence where the bottom player has shrimped onto their side but failed to recover full guard.

Key mechanics

• ·Far-side cross-face or collar grip locks the opponent's upper body before the cut.
• ·Bottom shin pins the near-side hip — the bottom player cannot turn into you.
• ·Cutting knee slides across the top of the thigh, not over the top of the knee.
• ·Hips stay low and forward through the cut — no rising off the opponent.
• ·Free hand controls the bottom player's far-side wrist or inside the collar.
• ·Cutting foot lands flat on the mat behind the bottom player's hamstring.

Common mistakes

1. 1. Rising off the opponent during the cut

   Why: Lifting the hips loses the pressure that pins the bottom player's hip. They recover guard the moment weight comes off.

   Fix: Cue: chest stays heavy through the cut. Drive forward, not up.

2. 2. Cutting over the knee, not the thigh

   Why: A cut placed too low gets jammed against the kneecap and stalls. The knee shield re-engages and the pass dies.

   Fix: Aim the cut at the top third of the thigh, just above the knee.

3. 3. No cross-face or collar grip

   Why: Without an upper-body anchor the bottom player frames into your face and shrimps out before the cut finishes.

   Fix: Lock the cross-face or deep collar grip before the cut starts. No grip, no cut.

4. 4. Letting the bottom shin float

   Why: A floating bottom shin lets the bottom player turn into you and recover full guard underneath.

   Fix: Pin the near-side hip with the bottom shin throughout. Shin glued to the mat.

5. 5. Releasing the underhook to finish

   Why: The underhook is what prevents the back-take counter. Releasing it mid-pass invites the bottom player to take your back.

   Fix: Keep the underhook from start to finish. Release it only after both shoulders are pinned.

Tactical vulnerabilities

Defensive openings this technique creates if executed poorly.

• ·Back-take if the underhook is given up mid-pass.
• ·Full-guard recovery if the bottom shin floats off the mat.
• ·Kimura threat on the cutting arm if the elbow flares away from the body.

What mmaGPT detects in your knee cut pass

• ·Cut position on the thigh (top third vs over the kneecap).
• ·Chest height through the cut (heavy vs rising).
• ·Underhook grip retention through the sequence.
• ·Bottom-shin contact with the mat (pinning vs floating).
• ·Time-to-finish from cut start to side-control consolidation.

Sample mmaGPT analysis

Structured output as it would appear in a real session.

Coaching correction

The knee cut breaks for one reason at the intermediate level: the chest rises. Every other flaw is downstream of that. Fix the rising habit with positional drilling against a cooperative partner who taps your back every time you lift off them. Two weeks of that and the chest stays heavy automatically. Then layer in the live elements — a resisting underhook fight, an active retention chain, a sneaky back-take threat. The pass should win at least 60 percent of clean entries by the time the chest is reliably heavy.

Drill ladder

1. baseline

   Static cut reps, no resistance

   3 rounds of 10 cuts

   Cue: Heavy chest. Drive forward.

2. progression

   Cut vs token resistance

   3 rounds of 6 cuts with a recovering partner

   Cue: Maintain the cross-face. Pin the bottom shin.

3. live

   Knee-cut-only passing rounds

   3 rounds of 3 minutes — knee cut only

   Cue: Finish or reset. No alternative passes allowed.

Beginner / intermediate / advanced

Sparring application

In a live roll the knee cut should be your default pressure pass against half guard and knee-shield positions. If it is failing more than half the time, video one round of passing attempts and review where the cut breaks — almost always at the same point. Fix that one point and the pass success rate moves dramatically inside one training cycle.

Session cues

• ·Drive forward, not up.
• ·Cut the thigh, not the knee.
• ·Pin the bottom shin.
• ·Keep the underhook.

Defensive considerations

• ·Releasing the underhook to finish concedes the back.
• ·Cutting too aggressively leaves the cutting leg vulnerable to a heel hook in no-gi.
• ·A rising chest converts a pass attempt into a guard-recovery sequence.

Video

FAQ

What is the most common knee-cut mistake?

The chest rises during the cut. Fix this and the pass success rate roughly doubles inside two weeks of drilling.

Should I cut over the kneecap or the thigh?

The top third of the thigh. Cutting over the kneecap stalls against the bony resistance and lets the knee shield re-engage.

Why do I keep getting my back taken on the cut?

You are releasing the underhook to finish. Hold it until both shoulders are pinned in side control.

Can the system analyze passing rounds?

Yes. Upload a 60-second clip of knee-cut attempts and the analysis flags the chest-height and underhook-release patterns directly.