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Knee Slice Pass | BJJ Technique | BJJ Graph

Oct 25, 202516 min read

Knee Slice Pass

bjjtransitionguard_passinghalf_guardfundamental

Visual Execution Sequence

From half guard top position, you establish strong underhook control and crossface pressure while your opponent’s legs control your trapped leg. You drive your knee forward and across your opponent’s bottom leg, creating a slicing motion that cuts through their guard structure. Simultaneously, you drive your shoulder into their face with crossface pressure while controlling their far arm or hip. As your knee clears their bottom leg, you slide your trapped leg free while maintaining heavy shoulder pressure, transitioning smoothly into side control with dominant position secured.

One-Sentence Summary: “From half guard top, you slice your knee across opponent’s bottom leg while maintaining crossface pressure, clearing their guard to establish side control.”

Execution Steps

  1. Setup Requirements: Establish underhook with inside arm, create strong crossface pressure with head/shoulder, control opponent’s far arm or hip with free hand

  2. Initial Movement: Drive weight forward onto opponent’s chest, begin directing knee forward and across their bottom leg in slicing motion

  3. Opponent Response: Opponent attempts to maintain half guard by gripping trapped leg, creates frames to prevent crossface, works to recover full guard

  4. Adaptation: Adjust knee angle and pressure based on opponent’s leg position; increase crossface pressure if opponent frames; shift hip positioning to prevent guard recovery

  5. Completion: Drive knee fully across bottom leg while extracting trapped leg; settle hips to mat as knee clears; establish side control chest-to-chest position

  6. Consolidation: Secure crossface control, establish hip pressure, control near arm with underhook, prevent opponent’s escape attempts

Key Technical Details

  • Grip Requirements: Underhook with inside arm (deep and tight), crossface with head/shoulder pressure, far arm controlling opponent’s arm or hip
  • Base/Foundation: Weight distributed forward onto opponent; inside knee driving across as fulcrum; outside leg providing base and driving power
  • Timing Windows: Execute as opponent’s frames weaken or when creating sweep attempt; optimal timing when opponent’s legs momentarily relax
  • Leverage Points: Knee acts as wedge separating guard; crossface creates immobilizing pressure; underhook prevents opponent from turning away
  • Common Adjustments: If knee gets stuck, adjust angle more acute or change direction slightly; if opponent frames effectively, increase crossface pressure before continuing slice

Common Counters

Opponent defensive responses with success rates and conditions:

Decision Logic for AI Opponent

If [underhook not established]:
- Execute [[Underhook Counter]] (Probability: 50%)
- Establish deep underhook to prevent forward pressure

Else if [knee slice starting]:
- Execute [[Knee Shield Recovery]] (Probability: 45%)
- Create knee shield frame to block slicing motion

Else if [crossface pressure weak]:
- Execute [[Hip Escape]] (Probability: 35%)
- Escape hips and recover guard

Else [pass progressing]:
- Execute [[Lockdown]] (Probability: 40%)
- Lock feet to prevent leg extraction

Expert Insights

John Danaher

“The knee slice pass is fundamentally about creating an insurmountable structural problem for your opponent - you’re driving a wedge between their legs while simultaneously controlling their upper body with the crossface. The genius of this pass is that it attacks the guard at its weakest point - the space between the legs - while preventing the primary defensive responses through upper body control. The key technical detail is understanding that the knee must move in a precise arc, not just forward but slightly upward and across, creating a cutting motion that makes it nearly impossible for the opponent to keep their legs together. The crossface is not optional - it’s the control mechanism that prevents them from turning into you or creating frames.”

Gordon Ryan

“This is my highest-percentage pass from half guard because it’s so reliable when you understand the pressure points. The crossface is everything - if you can make them carry your shoulder weight on their face, they can’t create effective frames. I’ve passed world champions with this because once the knee starts slicing through and they’re dealing with heavy shoulder pressure, they have no good options. The timing I look for is when they’re trying to recover full guard or attempting a sweep - that’s when their legs open slightly and I drive the knee through. In competition, I probably complete this pass 80% of the time when I can establish the proper crossface. The detail everyone misses is that your hips need to be heavy and low as the knee slices - you’re not just moving the knee, you’re driving your entire body through.”

Eddie Bravo

“From the 10th Planet perspective, we see the knee slice as one of the fundamental threats that forces the bottom player into defensive mode. What I teach is recognizing when the knee slice is coming and having multiple contingency plans - the lockdown, the electric chair setup, the underhook battle. But when I’m on top and using the knee slice, I’m thinking about creating a systematic attack where the pass is just one option. If they defend the knee slice hard, I have the back take. If they try to underhook, I have the darce or anaconda. The pass itself is high percentage, but it’s even more valuable as part of a system that creates multiple simultaneous threats they can’t all defend.”

Common Errors

Error 1: Attempting pass without establishing crossface pressure

  • Why It Fails: Opponent can create effective frames and prevent forward pressure; guard retention becomes much easier
  • Correction: Always establish strong crossface before initiating knee slice; head/shoulder must be driving into their face
  • Recognition: Opponent easily creating frames and blocking passing attempt; no forward pressure established

Error 2: Driving knee straight forward instead of slicing across

  • Why It Fails: Straight forward motion allows opponent to keep legs together; slicing motion is what separates the guard
  • Correction: Drive knee forward and across in arc motion, cutting through the space between legs
  • Recognition: Knee getting stuck or stalled by opponent’s legs staying together

Error 3: Lifting hips too high during pass

  • Why It Fails: High hips reduce pressure and allow opponent to hip escape or recover guard
  • Correction: Keep hips low and heavy throughout pass; weight should be driving down onto opponent
  • Recognition: Opponent easily escaping hips away; feeling light on top; opponent recovering guard

Error 4: Failing to control far arm or hip

  • Why It Fails: Opponent can use far arm to create frames or assist in guard recovery
  • Correction: Control far arm with free hand or post on hip to prevent movement
  • Recognition: Opponent creating effective frames with far arm; blocking pass progression

Error 5: Not following hip position as knee slices

  • Why It Fails: Knee may clear but hips remain in half guard position, allowing re-guard
  • Correction: As knee slices through, immediately shift hips to side control position
  • Recognition: Knee clears but opponent can still recover guard; positional transition incomplete

Timing Considerations

  • Optimal Conditions: Opponent attempting sweep or guard recovery (legs momentarily open); strong crossface established; opponent’s frames weakened
  • Avoid When: Opponent has deep underhook on you; knee shield actively framing; you lack crossface control; opponent has lockdown established
  • Setup Sequences: After opponent fails sweep attempt; when transitioning from other passing attempts; after establishing underhook and crossface dominance
  • Follow-up Windows: Must establish side control immediately (within 1-2 seconds) after knee clears to prevent guard recovery

Prerequisites

  • Technical Skills: Basic half guard top control; crossface pressure fundamentals; underhook control; positional weight distribution
  • Physical Preparation: Hip mobility for knee slicing motion; shoulder/neck strength for maintaining crossface; core strength for pressure maintenance
  • Positional Understanding: Half guard mechanics; side control establishment; guard passing principles; angle creation
  • Experience Level: Beginner-Intermediate - fundamental passing technique teachable at early stages with refinement over time

Knowledge Assessment

  1. Mechanical Understanding: “What creates the passing force in the knee slice pass?”

    • A) Only the knee movement
    • B) Only the crossface pressure
    • C) The combination of knee slicing motion, crossface pressure, and underhook control
    • D) Opponent’s cooperation
    • Answer: C

  2. Timing Recognition: “When is the optimal moment to initiate the knee slice?”

    • A) When opponent has deep underhook
    • B) When opponent’s legs are locked tight
    • C) When opponent’s guard opens slightly (sweep attempt, guard recovery) and crossface is established
    • D) At any random time
    • Answer: C

  3. Error Prevention: “What is the most critical error in knee slice execution?”

    • A) Slicing knee too fast
    • B) Attempting pass without establishing crossface pressure first
    • C) Using underhook control
    • D) Driving weight forward
    • Answer: B

  4. Setup Requirements: “What must be established before attempting knee slice pass?”

    • A) Only underhook control
    • B) Strong crossface pressure, underhook control, and far arm/hip control
    • C) Both legs must be free
    • D) Opponent must be tired
    • Answer: B

  5. Adaptation: “How do you adjust if opponent creates knee shield during pass?”

    • A) Force knee through harder
    • B) Give up immediately
    • C) Increase crossface pressure, adjust knee angle, or transition to different pass
    • D) Pull back completely
    • Answer: C

Variants and Adaptations

  • Gi Specific: Can use gi grips for crossface (collar grip) and far arm control (sleeve grip); pants grip for hip control
  • No-Gi Specific: Crossface with shoulder pressure and head position; underhook and whizzer positions more critical without gi grips
  • Self-Defense: Highly effective for establishing control and moving to dominant position in street scenario
  • Competition: Fundamental passing technique effective at all skill levels; high-percentage in gi and no-gi competition
  • Size Differential: Larger practitioners can use weight advantage for crossface pressure; smaller practitioners rely more on timing and angle precision

Training Progressions

  1. Solo Practice: Practice knee slicing motion and hip positioning without partner to develop movement pattern
  2. Cooperative Drilling: Partner allows pass with minimal resistance to develop feel for proper angles and pressure points
  3. Resistant Practice: Partner provides progressive defensive resistance requiring timing refinement and pressure adjustment
  4. Sparring Integration: Implement pass during live rolling from half guard top position
  5. Troubleshooting: Analyze failed passing attempts - usually crossface pressure, knee angle, or timing issues requiring correction

LLM Context Block

Purpose: This section contains structured decision-making logic for AI opponents, narrative generation, and game engine processing.

Execution Decision Logic

decision_tree:
  conditions:
    - name: "Crossface Establishment Check"
      evaluation: "crossface_pressure_strong AND head_position_dominant"
      success_action: "proceed_to_underhook_check"
      failure_action: "opponent_frame_creation"
      failure_probability: 50
 
    - name: "Underhook Control Check"
      evaluation: "underhook_deep AND far_arm_controlled"
      success_action: "initiate_knee_slice"
      failure_action: "opponent_underhook_counter"
      failure_probability: 45
 
    - name: "Knee Slice Execution"
      evaluation: "knee_angle_correct AND pressure_maintained"
      success_action: "complete_pass_to_side_control"
      failure_action: "opponent_guard_retention"
      failure_probability: 35
 
  final_calculation:
    base_probability: "success_probability[skill_level]"
    applied_modifiers:
      - setup_quality: +15
      - timing_precision: +10
      - opponent_fatigue: +10
      - knowledge_test: +10
      - position_control: +15
    formula: "base_probability + sum(modifiers) - sum(counters)"

Common Troubleshooting Patterns

troubleshooting:
  - symptom: "Knee gets stuck and won't slice through"
    likely_cause: "Incorrect knee angle or insufficient crossface pressure"
    diagnostic_questions:
      - "Is knee moving in arc/slicing motion or straight forward?"
      - "Is crossface pressure preventing opponent from framing?"
      - "Are hips low and driving forward?"
    solution: "Adjust knee to more acute slicing angle; increase crossface pressure to prevent frames; keep hips low and heavy"
 
  - symptom: "Opponent easily recovers guard after knee clears"
    likely_cause: "Hips not following knee position; delay in establishing side control"
    diagnostic_questions:
      - "Are hips shifting to side control as knee clears?"
      - "Is there delay between knee clearing and side control?"
      - "Is weight staying on opponent throughout transition?"
    solution: "Immediately shift hips to side control position as knee clears; maintain constant forward pressure; no pause in transition"
 
  - symptom: "Opponent creates effective frames blocking pass"
    likely_cause: "Insufficient crossface pressure or far arm not controlled"
    diagnostic_questions:
      - "Is shoulder driving into opponent's face?"
      - "Is far arm controlled or free to frame?"
      - "Is head position dominant and low?"
    solution: "Increase crossface pressure with shoulder; control far arm or post on hip; ensure head position is low and forward"

Timing and Setup Guidance

timing_guidance:
  optimal_windows:
    - condition: "Opponent attempting sweep causes guard to open momentarily"
      success_boost: "+20%"
      recognition_cues: ["Legs separating for sweep attempt", "Weight shifting", "Focus on sweep execution"]
 
    - condition: "Strong crossface established with opponent's frames weakened"
      success_boost: "+15%"
      recognition_cues: ["Head pressure heavy", "Opponent unable to create frames", "Underhook secured"]
 
    - condition: "Opponent trying to recover full guard"
      success_boost: "+12%"
      recognition_cues: ["Bottom leg extending", "Attempt to insert knee", "Guard opening"]
 
  avoid_windows:
    - condition: "Opponent has deep underhook on you"
      success_penalty: "-25%"
      recognition_cues: ["Their underhook deeper than yours", "They're turning into you", "Strong underhook control"]
 
    - condition: "Active knee shield frame established"
      success_penalty: "-20%"
      recognition_cues: ["Knee creating strong frame", "Bottom leg blocking path", "Frame preventing forward movement"]
 
    - condition: "Lockdown secured on trapped leg"
      success_penalty: "-30%"
      recognition_cues: ["Feet locked together", "Trapped leg immobilized", "Cannot extract leg"]
 
setup_sequences:
  - sequence_name: "Crossface to Knee Slice"
    steps:
      - "Establish dominant crossface position"
      - "Secure underhook control"
      - "Drive knee across as opponent's guard opens"
    success_boost: "+18%"
 
  - sequence_name: "Failed Sweep to Pass"
    steps:
      - "Opponent attempts sweep from half guard"
      - "Defend sweep and establish crossface"
      - "Exploit opened guard with knee slice"
    success_boost: "+15%"

Narrative Generation Prompts

narrative_prompts:
  setup_phase:
    - "You establish dominant position in half guard top with strong underhook and crossface pressure."
    - "Your opponent feels the weight of your shoulder on their face, limiting their defensive options."
    - "You wait for the moment their guard opens slightly - the window for your pass."
 
  execution_phase:
    - "Your knee drives forward and across in a slicing motion, cutting through the space between their legs."
    - "The crossface pressure intensifies as you drive your weight forward, preventing frames."
    - "Your trapped leg begins to extract as the knee clears their bottom leg."
 
  completion_phase:
    - "The knee completes its arc, fully clearing their guard structure."
    - "You immediately shift your hips to side control position while maintaining pressure."
    - "Side control is established - your crossface and underhook securing dominant position."
 
  failure_phase:
    - "Your opponent establishes a deep underhook, blocking your forward pressure."
    - "Their knee shield frames against your chest, stopping the slicing motion."
    - "The guard remains intact - your passing attempt is defended."

Image Generation Prompts

image_prompts:
  setup_position:
    prompt: "Brazilian Jiu-Jitsu half guard top position, top practitioner with underhook control and strong crossface pressure, bottom practitioner's legs controlling one leg, both in gi, technical illustration style"
    key_elements: ["Underhook established", "Crossface pressure", "Half guard position", "Control points"]
 
  mid_execution:
    prompt: "BJJ knee slice pass in motion, top practitioner's knee driving across bottom leg in slicing motion, shoulder pressure on face, underhook deep, dynamic passing action captured, technical illustration"
    key_elements: ["Knee slicing motion", "Crossface pressure", "Underhook control", "Guard opening"]
 
  completion_position:
    prompt: "BJJ side control position, top practitioner with chest-to-chest pressure, crossface established, underhook secured, bottom practitioner's guard cleared, control established, technical illustration style"
    key_elements: ["Side control position", "Crossface control", "Underhook secured", "Dominant position"]

Audio Narration Scripts

audio_scripts:
  instructional_narration:
    script: "From half guard top, establish strong underhook and crossface pressure. Wait for your opponent's guard to open slightly. Drive your knee forward and across in a slicing motion while maintaining heavy shoulder pressure on their face. As your knee clears their bottom leg, immediately shift your hips to side control position. Secure the position with crossface and underhook control."
    voice: "Onyx"
    pace: "Moderate"
    emphasis: ["crossface pressure", "slicing motion", "immediately shift", "secure the position"]
 
  coaching_cues:
    script: "Underhook deep. Crossface heavy. Feel the opening. Slice that knee through. Drive forward. Hip pressure down. Clear the leg. Shift to side control. Lock it down. Perfect pass."
    voice: "Onyx"
    pace: "Energetic"
    emphasis: ["slice that knee", "drive forward", "shift to side control", "perfect pass"]
 
  competition_commentary:
    script: "Watch the setup here. Beautiful crossface pressure established. Underhook is deep. Opponent's guard opens momentarily - there's the window. Knee slicing through now - perfect angle and pressure. The guard is cleared. Immediate transition to side control. Textbook knee slice pass. That's how it's done at the highest level."
    voice: "Onyx"
    pace: "Fast"
    emphasis: ["beautiful crossface", "perfect angle", "immediate transition", "textbook"]

Competition Applications

  • IBJJF Rules: Fundamental passing technique scoring 3 points for guard pass to side control; legal at all belt levels
  • No-Gi Competition: Highly effective without gi; requires strong pressure and positioning over grip control
  • Self-Defense Context: Excellent for establishing control and advancing position in street scenario
  • MMA Applications: Effective in MMA with consideration for striking defense; crossface provides control while advancing position

Historical Context

The knee slice pass has become one of the most fundamental and widely taught guard passes in modern Brazilian Jiu-Jitsu. Its effectiveness across gi and no-gi contexts, combined with its mechanical reliability, has made it a staple technique taught from white belt through black belt. The pass exemplifies efficient guard passing principles: controlling the upper body while creating space to clear the legs.

Safety Considerations

  • Controlled Application: Apply crossface pressure progressively; avoid sudden or excessive neck pressure
  • Mat Awareness: Ensure adequate space for passing movement without obstacles
  • Partner Safety: Be mindful of crossface pressure on partner’s neck/face; communicate during drilling
  • Gradual Progression: Build up speed and pressure gradually during learning phase

Position Integration

Common combinations and sequences:

  • Underhook Pass - Complementary half guard passing technique using underhook leverage
  • Long Step Pass - Alternative half guard pass with different mechanics
  • Crossface Control - Essential control element for knee slice pass
  • Stack Pass - Different passing style with some mechanical similarities

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