Knee Slice from Half

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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) Success Rate: 68%

Possible Outcomes

Result	Position	Probability
Success	Side Control	75%
Failure	Half Guard	15%
Counter	Deep Half Guard	10%

Attacker vs Defender

	Attacker	Defender
Focus	Execute technique	Prevent or counter
Key Principles	Establish crossface control before initiating the pass to el…	Deny the crossface at all costs - without it, the passer can…
Options	6 execution steps	4 defensive options

Playing as Attacker

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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

Execution Steps

• Establish crossface control: Drive your shoulder across the opponent’s face and into their far shoulder, using your forearm to cr…

• Secure the underhook: Thread your free arm under their far armpit, gripping around their back or their far lat muscle. Thi…

• Flatten the opponent: Using your underhook and crossface together, drive the opponent flat onto their back. Their bottom s…

• Position the slicing knee: Place your inside knee (the one on the same side as their half guard grip) directly on their inner t…

• Step back and drive the knee: Step your trapped foot backward while simultaneously driving your slicing knee across their legs tow…

• Clear the legs and establish side control: As your knee completes the slice and clears their bottom leg, immediately bring your trailing leg th…

Common Mistakes

• Attempting to slice the knee before establishing proper upper body control

  • Consequence: Opponent easily recovers full guard or sweeps you because they have freedom to frame and move
  • Correction: Always establish crossface and underhook first. Your upper body control must be locked in before any leg movement begins. Take an extra second to ensure the opponent is flattened and controlled.

• Slicing the knee in a straight line rather than at a 45-degree angle

  • Consequence: Your knee gets stuck on their leg, creating a stalemate position where you’re burning energy without making progress
  • Correction: Angle your knee toward their far hip, creating a diagonal cutting motion. Think of slicing across rather than driving straight through.

• Rising too high on your knees during the pass

  • Consequence: Loss of pressure allows opponent to create space, recover guard, or enter into leg entanglements
  • Correction: Keep your hips low and heavy throughout the entire pass. Your chest should stay close to their upper body, maintaining constant downward pressure.

Playing as Defender

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Key Principles

• Deny the crossface at all costs - without it, the passer cannot flatten you or control your head orientation, which is the foundation of their entire pass

• Win the underhook battle on the trapped-leg side, as your underhook provides the primary offensive pathway to sweeps and back takes while neutralizing their passing pressure

• Maintain your hip angle by staying on your side rather than allowing yourself to be flattened to your back, which eliminates all defensive and offensive options

• Use your knee shield as the first line of defense to manage distance and prevent the passer from establishing chest-to-chest pressure

• Keep your inside elbow connected to your inside knee to create an integrated defensive frame that cannot be easily collapsed

• React early to the passing attempt during the setup phase rather than waiting until the knee is already slicing through your guard

• Treat failed pass attempts as transition opportunities into sweeps, deep half entries, or back takes rather than simply returning to neutral half guard

Recognition Cues

• Opponent drives their shoulder across your face establishing crossface pressure while their weight shifts forward onto your upper body

• Opponent threads their far arm under your armpit to secure an underhook, pulling your torso toward them and attempting to flatten your shoulders to the mat

• Opponent repositions their inside knee onto your inner thigh or hip crease at approximately 45 degrees, angling their shin toward your far hip in preparation for the slice

• Opponent begins stepping their trapped foot backward while maintaining heavy forward pressure through their chest and shoulder

• You feel your bottom shoulder being driven flat to the mat while the opponent’s weight concentrates on your upper body rather than being distributed across your hips

Defensive Options

• Establish and maintain knee shield with forearm frame on opponent’s bicep and hip, creating a structural barrier that prevents the passer from closing distance and establishing chest pressure - When: Early in the pass attempt before opponent establishes crossface - this is your highest-percentage defense when timed correctly

• Fight aggressively for the underhook on the trapped-leg side by swimming your arm under their armpit and coming up to your side, then use the underhook to off-balance them and threaten sweeps or back takes - When: When opponent has begun establishing upper body control but has not yet locked in both crossface and underhook simultaneously

• Dive underneath opponent into deep half guard by getting your head below their hip line and establishing a deep underhook around their far leg, using their committed forward pressure against them - When: When opponent has established crossface and begun the knee slice motion - this is your emergency defense when early-stage prevention has failed

Variations

Knee Slice with Underhook Only: Variation used when you cannot establish the crossface due to opponent’s defensive posture. Focus entirely on the underhook control, using it to lift and flatten the opponent while your free hand posts on the mat for base. The knee slices on the underhook side, and you drive your shoulder into their jaw as you pass to establish late crossface during the transition. (When to use: Against opponents who defend their neck aggressively or in no-gi when collar ties are unavailable)

Knee Slice to Knee on Belly: Instead of settling into side control, continue the momentum of your knee slice directly into knee on belly position. As your knee clears their legs, plant it on their abdomen while maintaining the crossface and establishing a strong base with your other leg. This variation creates immediate submission threats and forces opponent into defensive reactions. (When to use: When opponent is anticipating side control and preparing defenses, or when you want to establish more dominant control immediately)

Reverse Knee Slice: Executed when you cannot get the underhook on the far side. Instead, you underhook on the near side (same side as your slicing knee) and drive your shoulder into their far shoulder. Your knee slices in the opposite direction, clearing their legs while you rotate to establish side control or north-south position. (When to use: When opponent blocks your far side underhook but leaves the near side exposed)

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.

Related Techniques

• Knee Slice Pass - Parent technique covering all knee slice variations

• Knee Cut Pass - Alternative pass from similar position with sharper angle

• Long Step Pass - Follow-up when knee slice is defended

• Underhook Pass - Alternative when underhook is established

• Leg Weave Pass - Counter to leg grab defense during knee slice

• Crossface Pass - Complementary technique emphasizing same upper body control

• Side Control - Primary ending position after successful pass

• Knee on Belly - Alternative ending position for more dynamic control

• Kimura from Half Guard - Submission threat available during passing sequence

• Deep Half Guard - Common counter position when opponent goes underneath

• Half Guard - Starting position for this pass

• Back Step Pass - Chain attack when knee slice is blocked