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.
Starting Position: Half Guard Ending Position: Side Control Success Rates: Beginner 45%, Intermediate 60%, Advanced 75%
Key Principles
- 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
- 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
- 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. (Timing: Before attempting any leg extraction)
- 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. (Timing: Immediately after establishing crossface)
- 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. (Timing: Continuous pressure as you prepare to move your knee)
- 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. (Timing: As opponent is flattened)
- 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. (Timing: Explosive movement coordinated with hip drive)
- 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. (Timing: Immediate transition as legs clear)
Opponent Counters
- 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.
- 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.
- 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.
- 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.
- 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.
Test Your Knowledge
Q1: Why is establishing the crossface before attempting the knee slice critical to the pass’s success? A: The crossface eliminates the opponent’s ability to turn into you and create defensive frames. It pins their bottom shoulder to the mat, flattening their posture and removing their strongest defensive position. Without the crossface, they can easily use their arms to create space, block your knee, or recover guard. The crossface also controls their head, which controls their entire body’s orientation.
Q2: What is the correct angle for the slicing knee, and why does this angle matter? A: The knee should slice at approximately 45 degrees toward the opponent’s far hip, not straight across their body. This angle matters because it creates the most efficient cutting motion that separates their legs while avoiding getting stuck on their thigh. A straight angle creates too much resistance, while too wide an angle sacrifices pressure and allows them to recover. The diagonal motion also naturally positions you for the side control transition.
Q3: How do you address an opponent who establishes a strong underhook during your knee slice attempt? A: First, recognize that their underhook significantly compromises your pass. You have several options: swim your arm over theirs to re-establish your underhook, grip their underhooking wrist and apply a kimura lock to neutralize the threat, or abandon the knee slice entirely and switch to a different passing angle such as the backstep or long step. Never force the pass against a strong underhook as it leads to scrambles or sweeps.
Q4: What are the key differences between the knee slice and knee cut passes? A: While both involve driving your knee across opponent’s legs, the knee slice typically originates from half guard with one leg trapped and emphasizes a cutting motion with your shin bone, whereas the knee cut usually starts from open guard with both legs free and involves cutting with your knee itself at a sharper angle. The knee slice focuses more on upper body control and flattening, while the knee cut often emphasizes hip switch and angle creation. They complement each other in passing systems.
Q5: Why is it important to immediately establish side control consolidation after completing the knee slice? A: The moment your legs clear represents your most vulnerable point in the pass. If you don’t immediately secure side control with proper hip pressure and crossface maintenance, the opponent can turn back into you and recover guard. Proper consolidation means landing heavy with chest-to-chest pressure, controlling the far hip to prevent rotation, and maintaining the crossface until you’ve fully stabilized. Many practitioners successfully slice their knee but lose the position by failing to consolidate properly.
Q6: What should you do if opponent grabs your slicing leg and prevents it from clearing? A: Don’t fight the grip with pure strength. Instead, use your underhook to off-balance them away from your trapped leg, creating the angle needed to free it. Alternatively, you can switch to a leg weave pass by stepping your free leg over their grip and using downward pressure to break their hold. Another option is to redirect entirely to an over-under pass or different passing angle if their grip is too strong.
Safety Considerations
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.
Position Integration
The Knee Slice from Half Guard serves as a central technique in virtually all modern guard passing systems, creating a hub from which numerous other techniques branch. It connects directly to the fundamental half guard passing sequence, working in combination with the knee cut, long step, and underhook passes to create a comprehensive system. When the knee slice is defended, practitioners naturally flow into backstep passes, leg weaves, or quarter guard consolidation. From a defensive perspective, understanding the knee slice mechanics informs half guard bottom strategy, as preventing the crossface and maintaining the underhook become primary defensive objectives. The pass also integrates forward into submission chains - successful completion often leads directly to kimura attacks, far side armbars, or north-south choke opportunities. In the broader context of positional hierarchy, the knee slice represents the critical transition from neutral positions into top control, making it essential for competitors who prioritize a top-game strategy. It functions equally well in gi and no-gi grappling, making it one of the most universally applicable passing techniques across all rule sets and competition formats.
Expert Insights
- Danaher System: The knee slice from half guard represents one of the most biomechanically sound passing methods available because it addresses the fundamental problem of guard passing: how to control the opponent’s hip mobility while maintaining pressure. The technique succeeds because it creates what I call ‘stacked control points’ - the crossface controls the head, the underhook controls the shoulder, and the slicing knee controls the hips. These three points of control, when properly coordinated, make it geometrically impossible for the opponent to maintain their guard structure. The key insight most practitioners miss is that the pass is won or lost in the first three seconds, not during the actual leg clearing. If you cannot flatten the opponent and eliminate their ability to turn into you, the pass will fail regardless of your knee slice mechanics. This is why systematic development of the upper body control must precede any focus on the leg extraction. Additionally, the angle of the slice is not arbitrary - the 45-degree trajectory represents the shortest path between their hip structure while maintaining maximum pressure on their upper body. Understanding this geometry allows you to make continuous forward progress even against resistance.
- Gordon Ryan: In competition, the knee slice from half guard is one of my highest percentage passes because it works against every body type and style. What makes it so effective at the elite level is that it creates an immediate dilemma: defend the crossface or defend the underhook. Most opponents can handle one threat, but both simultaneously overloads their defensive capacity. My personal variation emphasizes extremely heavy crossface pressure - I want their jaw to feel like it’s being driven through the mat. This level of discomfort forces them to make mistakes or abandon optimal defensive positions. The timing of the pass is critical in matches. I typically set it up after opponent makes an initial defensive effort and has to reset. That split second of transition is when I establish my grips and flatten them. Against world-class half guard players, I often use the knee slice as a setup rather than a finish, knowing they’ll defend it predictably, which opens up my backstep or far side attacks. The pass also has tremendous value in wearing down opponents - even failed knee slice attempts drain their energy as they work to prevent being flattened. In a long match, I can return to the knee slice repeatedly, each time meeting less resistance.
- Eddie Bravo: The knee slice from half guard is interesting because it represents the orthodox approach to a position where I typically advocate for unorthodox solutions. However, I’ve come to respect this pass immensely because it shuts down so many of the 10th Planet half guard entries before they can develop. When someone establishes that crossface and flattens me in half guard, all my underhook battles, lockdown entries, and electric chair setups become significantly harder. This has informed how I teach the position from both sides. From top, I tell students the knee slice is your ‘reset button’ - when things get complicated in half guard and you’re dealing with multiple grips and threats, establishing the crossface and flattening them simplifies everything back to fundamental passing principles. From bottom, defending the knee slice becomes the primary objective because if it succeeds, you’ve lost all your offensive potential. In no-gi especially, where the knee slice is even more powerful due to reduced friction, I emphasize maintaining that inside space and never letting them flatten your shoulders. The battle for that inside position - their crossface versus your frames and underhook - represents the entire game. One interesting adaptation I’ve developed is using the opponent’s knee slice attempt as an entry to truck position by diving under their slicing leg as they commit, but that’s an advanced counter that requires perfect timing.