The Knee Slice from Half Guard is one of the most fundamental and high-percentage guard passes in Brazilian Jiu-Jitsu. This technique exploits the half guard player’s commitment to the inside position by creating a powerful angle that drives your knee across their legs while establishing dominant upper body control. The pass works by combining forward pressure with lateral movement, using your knee as a wedge to separate the opponent’s legs while your hips drive through the opening.
What makes this pass particularly effective is its ability to shut down the bottom player’s primary defensive tools - the underhook and the inside space. By controlling the crossface and establishing a strong underhook yourself, you neutralize their framing attempts while simultaneously flattening them to the mat. The knee slice motion creates a dilemma: if they focus on stopping your knee, they lose upper body control; if they fight your crossface, your knee slides through uncontested.
This pass represents a cornerstone of modern guard passing systems because it works equally well in gi and no-gi, against all body types, and connects seamlessly to other passing options. When executed with proper timing and pressure, the knee slice becomes nearly unstoppable, forcing the opponent into increasingly desperate defensive reactions that open them up to back takes, mount transitions, or submission attacks.
From Position: Half Guard (Top)
Key Attacking Principles
What are the key principles for executing Knee Slice from Half?
- Establish crossface control before initiating the pass to eliminate defensive frames
- Drive your knee at a 45-degree angle across the legs rather than straight through
- Keep your hips heavy and close to the opponent throughout the pass
- Use your underhook to lift and flatten the opponent’s torso
- Maintain forward pressure while stepping the trapped leg back
- Control the far side hip to prevent re-guard attempts
- Transition smoothly to side control consolidation immediately after passing
Prerequisites
What do you need before attempting Knee Slice from Half?
- Top position in opponent’s half guard with your leg trapped
- Strong crossface established with your shoulder driving into their jaw
- Underhook secured on the far side under their armpit
- Opponent’s bottom shoulder pinned to the mat
- Your weight distributed forward onto their upper body
- Inside knee positioned near their hip line ready to slice
- Base hand posted on the mat for stability and pressure
Execution Steps
How do you execute Knee Slice from Half step by step?
- Establish crossface control: Drive your shoulder across the opponent’s face and into their far shoulder, using your forearm to create pressure on their jaw. This control point is critical - without it, they can create frames and prevent your pass. Your weight should be forward, making it difficult for them to turn into you or establish an underhook.
- Secure the underhook: Thread your free arm under their far armpit, gripping around their back or their far lat muscle. This underhook serves multiple purposes: it lifts their shoulder off the mat, prevents them from turning away, and gives you control over their torso rotation. Pull their upper body toward you while maintaining the crossface pressure.
- Flatten the opponent: Using your underhook and crossface together, drive the opponent flat onto their back. Their bottom shoulder should be pinned to the mat, eliminating their ability to come up on their side. This flattening motion removes most of their defensive power and makes the leg extraction significantly easier.
- Position the slicing knee: Place your inside knee (the one on the same side as their half guard grip) directly on their inner thigh or hip crease. Your shin should be angled approximately 45 degrees relative to their body, pointing toward their far hip. This angle is crucial - too straight and you’ll get stuck, too wide and you’ll lose pressure.
- Step back and drive the knee: Step your trapped foot backward while simultaneously driving your slicing knee across their legs toward their far hip. The motion should feel like you’re cutting through their guard with your shin bone as the blade. Keep your hips low and heavy, maintaining downward pressure throughout the movement. Your knee should slide across the top of their thigh, separating their legs.
- Clear the legs and establish side control: As your knee completes the slice and clears their bottom leg, immediately bring your trailing leg through to establish side control. Your hips should land heavy on their torso, with your crossface still active and your underhook controlling their far side. Transition immediately to side control consolidation, using chest-to-chest pressure and controlling their near hip to prevent re-guard.
Possible Outcomes
| Result | Position | Probability |
|---|---|---|
| Success | Side Control | 75% |
| Failure | Half Guard | 15% |
| Counter | Deep Half Guard | 10% |
Opponent Counters
How might your opponent counter Knee Slice from Half?
- Opponent establishes a strong underhook and comes up to their side (Effectiveness: High) - Your Response: Switch to a different passing angle such as the backstep or long step pass. You can also address their underhook by swimming your arm over theirs and re-establishing your underhook, or by transitioning to a kimura grip on their underhooking arm. → Leads to Half Guard
- Opponent frames on your hip and creates distance during the knee slice (Effectiveness: Medium) - Your Response: Tighten your crossface and use your underhook to pull them back toward you, collapsing their frame. Alternatively, redirect to an over-under pass or switch to a knee cut variation if they’re committed to extending. → Leads to Half Guard
- Opponent locks a deep half guard as you attempt to extract your leg (Effectiveness: High) - Your Response: Don’t force the pass. Instead, address the deep half guard position first by establishing a whizzer on their underhook, driving your weight back, and working specific deep half guard passing techniques. Only return to the knee slice once you’ve escaped the deep half entanglement. → Leads to Deep Half Guard
- Opponent grabs your slicing leg and prevents it from clearing (Effectiveness: Medium) - Your Response: Use your grip on their far side to off-balance them away from your trapped leg. You can also switch to a leg weave pass, using your free leg to step over their grip and applying pressure to break their hold. → Leads to Half Guard
- Opponent turns away and attempts to take your back during the pass (Effectiveness: Low) - Your Response: This is often a positive development. Maintain your crossface control, sprawl your hips back, and establish front headlock control. From here, you have strong back take opportunities or can transition to turtle attacks. → Leads to Side Control
Safety Considerations
What are the safety concerns for Knee Slice from Half?
The knee slice pass is generally safe for both practitioners when performed correctly, but several precautions should be observed. The primary safety concern is avoiding excessive pressure on the opponent’s jaw with the crossface, particularly in training situations. Apply firm control without cranking their neck or driving upward into their jaw, which can cause neck strain or jaw injuries. When slicing your knee across, be mindful not to drive your knee directly into their thigh muscle with excessive force, as this can cause painful bruising or muscle damage. In no-gi situations, ensure your forearm isn’t creating a choke across their throat when establishing the crossface. For the person playing bottom, avoid explosive or jerky movements when defending the pass, as sudden direction changes while your legs are entangled can lead to knee injuries. Both partners should communicate about pressure levels, especially when drilling, and the bottom player should tap if experiencing any sharp pain in their knees or hips during the passing motion.