Why is securing the underhook before attempting to flatten the opponent critical to the success of this pass?

The underhook provides the primary control mechanism that prevents the bottom player from turning into you or establishing their own underhook. Without it, the opponent can easily create frames, turn to face you, or initiate sweeps. The underhook acts as both offensive control (allowing you to manipulate their posture) and defensive protection (preventing their offensive options from half guard). Attempting to flatten without the underhook results in a scramble situation where the bottom player has equal or superior control options.

What is the primary purpose of controlling the opponent's near hip during the underhook pass, and what happens if this control is neglected?

Controlling the near hip prevents the opponent from using hip escape (shrimping) movements to create the angle and distance needed to recover full guard or initiate sweeps. The hip is the mobility center of the bottom player's defensive movement. Without this control, even with good underhook and crossface, the opponent can shrimp away, creating space to re-establish their guard structure or insert knee shields. The near hip control works in conjunction with the underhook to create a pinning system that immobilizes the opponent's core.

Explain the biomechanical principle behind driving your shoulder into the opponent's chest while maintaining the underhook, and how this creates a flattening effect?

The shoulder drive creates a cross-body lever system where opposing forces work simultaneously. The underhook pulls their far shoulder toward you while your near shoulder pushes their near shoulder away from you. This creates rotational torque that flattens their spine against the mat. Additionally, the shoulder pressure on the chest restricts diaphragm expansion, making it uncomfortable to maintain a defensive posture on their side. The weight distribution through the shoulder transfers your body mass efficiently onto their frame, collapsing their structure without requiring you to lift your hips, which would create escape space.

How should you respond if the opponent establishes a lockdown on your trapped leg while you have the underhook position?

First, maintain all upper body control (underhook and crossface) to prevent sweeps while addressing the lockdown. Focus on breaking the lockdown by driving your trapped ankle toward the mat, creating a figure-four breaking position with your legs. Keep your weight forward and low to prevent the opponent from using the lockdown to create angles for electric chair or other attacks. If necessary, temporarily abandon leg extraction and work to break the lockdown first, potentially by driving your free knee across their body to relieve pressure on the trapped leg, then return to standard passing mechanics once the lockdown is broken.

What are the key differences in executing the underhook pass against a knee shield half guard versus a traditional half guard with no shield?

Against knee shield, the primary challenge is dealing with the extended frame that prevents chest-to-chest pressure. You must first address the knee shield by either controlling the knee and driving it to the mat, stepping over it, or transitioning to a different passing angle (like knee cut). The underhook remains important but the crossface pressure is harder to establish initially. Against traditional half guard without knee shield, you can more directly establish chest-to-chest pressure and begin the flattening process immediately. The traditional half guard allows faster entry into the flattening phase but may have stronger lockdown or underhook battle threats, while knee shield provides more initial defensive structure but less sweep threat once bypassed.

Why is it important to keep your base wide with your free leg during the underhook pass, and how does this affect your passing mechanics?

A wide base with the free leg posted creates stability against the opponent's bridging, hip bump, and off-balancing attempts. With your weight forward and one leg trapped, you're potentially vulnerable to sweeps if your base is narrow. The wide post allows you to distribute weight effectively while maintaining mobility to adjust to the opponent's movements. It also creates the angle needed to drive your trapped knee across their thigh during leg extraction. A narrow base makes you top-heavy and easy to tip over, while a wide base allows you to stay heavy on top while remaining structurally sound and able to generate the hip movement needed to clear your trapped leg.

Underhook Pass Attacker | BJJ Technique Guide

The Underhook Pass is a fundamental pressure passing technique used to advance from half guard top position to side control. This pass exploits the powerful control provided by securing an underhook on the bottom player’s far side, combined with strategic weight distribution and hip pressure to flatten the opponent and clear the leg entanglement. The technique is built on the principle of controlling the opponent’s shoulder and hip simultaneously, creating a cross-body pressure system that limits their defensive frames and movement options. The underhook provides both offensive control and defensive protection, preventing the bottom player from establishing their own underhook or recovering full guard. This pass is particularly effective against players who rely on knee shield or traditional half guard retention, as it addresses their primary defensive structures through systematic breakdown and methodical advancement.

From Position: Half Guard (Top)

Key Attacking Principles

What are the key principles for executing Underhook Pass?

Secure underhook on far side before initiating pass
Drive shoulder pressure into opponent’s chest to flatten
Control opponent’s near hip with free hand to prevent re-guard
Keep base wide and weight distributed forward
Clear trapped leg by driving knee across opponent’s thigh
Maintain chest-to-chest pressure throughout transition
Prevent opponent’s underhook battle at all costs

Prerequisites

What do you need before attempting Underhook Pass?

Top position in opponent’s half guard with leg trapped
Underhook secured on opponent’s far side arm
Head positioned on opponent’s chest, not allowing space
Wide base with free leg posted for stability
Opponent’s frames neutralized or controlled
Weight forward, hips low and heavy on opponent

Execution Steps

How do you execute Underhook Pass step by step?

Secure the underhook: From half guard top, thread your arm under opponent’s far armpit, securing a deep underhook. Your shoulder should drive into their chest while your hand reaches across their back, ideally gripping their far lat or belt. This underhook is the cornerstone of the entire passing sequence.
Establish crossface pressure: Place your head on opponent’s chest, driving your shoulder into their near pectoral muscle. This crossface pressure prevents them from turning into you or establishing their own underhook. Your ear should be tight to their sternum, minimizing space for their frames.
Control the near hip: With your free hand (non-underhook side), establish a firm grip on opponent’s near hip, pants, or belt. This grip prevents them from using hip movement to recover guard or create the angle needed for sweeps. Your palm should be facing down with fingers digging into their hip.
Flatten opponent’s posture: Drive your weight forward through your shoulder and chest, forcing opponent flat to their back. Simultaneously pull with your underhook and push with your crossface, creating opposing forces that collapse their defensive structure. Their shoulder blades should be pinned to the mat.
Clear the trapped leg: With opponent flattened, begin extracting your trapped leg by driving your knee across their thigh toward their hip. Maintain all upper body pressure while subtly shifting your hips backward. The key is small, methodical movements rather than explosive yanking that creates space.
Step over to side control: Once your knee clears their hip, step your free leg over their legs and establish side control. Keep your underhook and crossface pressure throughout the transition. Your chest should never leave their chest during this movement, maintaining constant pressure and connection.
Consolidate side control: Secure standard side control position with your underhook transitioning to far side control, your head positioned on the near side of their head, and your hips low and heavy. Establish all standard side control grips and pressure before considering further advancement or submission attacks.

Possible Outcomes

Result	Position	Probability
Success	Side Control	55%
Failure	Half Guard	25%
Counter	Closed Guard	10%
Counter	Dogfight Position	10%

Opponent Counters

How might your opponent counter Underhook Pass?

Bottom player establishes their own underhook, creating an underhook battle and preventing pass progression (Effectiveness: High) - Your Response: Immediately switch to whizzer control on their underhook arm, driving your weight into their shoulder while using your free hand to strip their grip or transition to alternative passes like the knee slice → Leads to Half Guard
Strong knee shield frame preventing chest-to-chest pressure and flattening (Effectiveness: High) - Your Response: Address the knee shield by controlling the knee with your free hand, driving it to the mat while maintaining underhook pressure. Alternatively, transition to knee cut pass or smash pass variations → Leads to Half Guard
Bottom player turns away going to turtle to escape pressure and leg clear (Effectiveness: Medium) - Your Response: Follow their rotation, maintaining the underhook and transitioning to back attack or using the momentum to complete the pass to opposite side control → Leads to Side Control
Electric chair or lockdown control on trapped leg, preventing extraction (Effectiveness: Medium) - Your Response: Focus on breaking the lockdown first by driving your trapped ankle to the mat and extracting your foot. Maintain upper body control throughout to prevent sweeps → Leads to Half Guard
Bottom player bridges explosively and hip escapes to recover closed guard (Effectiveness: Low) - Your Response: Ride the bridge by staying heavy and connected, allowing your body to move with theirs while maintaining underhook and crossface. Block far knee with your free hand to prevent guard closure → Leads to Closed Guard
Bottom player frames on bicep and hip escapes into dogfight position (Effectiveness: Medium) - Your Response: If they achieve the underhook and come to knees, immediately circle toward their back using your underhook depth advantage to prevent them from fully establishing the dogfight → Leads to Dogfight Position

Common Attacking Mistakes

What mistakes should you avoid when executing Underhook Pass?

1. Lifting weight up while trying to pass, creating space underneath

Consequence: Bottom player easily re-guards or sweeps as pressure is eliminated
Correction: Keep hips low and weight driving forward and down throughout entire sequence. Think of spreading your weight like a heavy blanket, not lifting to step over

2. Rushing the leg extraction before opponent is fully flattened

Consequence: Bottom player maintains mobility and uses frames to prevent pass or attempt sweeps
Correction: Be patient with the flattening process. Take time to completely neutralize their structure before attempting to clear your leg

3. Allowing opponent to get their underhook, creating a neutral underhook battle

Consequence: Pass progression stalls, and opponent has pathway to sweep or recover full guard
Correction: Secure your underhook early and maintain constant shoulder pressure to prevent them from establishing their own. If they get it, immediately address it

4. Head positioning too high or too far to one side, allowing opponent to turn

Consequence: Opponent can turn into you or away to turtle, escaping the pass
Correction: Keep your head centered on their chest with ear to sternum. This central position prevents rotation in either direction

5. Failing to control the near hip, allowing opponent to hip escape

Consequence: Opponent creates angle and distance to recover guard or initiate sweeps
Correction: Maintain active grip on near hip throughout the pass. This grip is as important as the underhook for preventing guard recovery

6. Base too narrow, making you susceptible to sweeps or off-balancing

Consequence: Opponent can use bridges, hip bumps, or other movements to destabilize and reverse position
Correction: Keep your free leg posted wide with knee out, creating a stable base that can’t be easily disrupted

Training Progressions

How do you train Underhook Pass (Attacker)?

Phase 1: Static Control (Weeks 1-2) - Establishing and maintaining the underhook and crossface position Practice securing the underhook from various half guard scenarios with compliant partner. Focus on grip placement, shoulder pressure, and maintaining position without attempting to pass. Partner provides light frames but doesn’t actively escape. Goal is to hold position for 2-3 minutes with proper pressure and posture.

Phase 2: Controlled Flattening (Weeks 3-4) - Developing pressure mechanics to flatten opponent From established underhook position, practice flattening partner to their back using weight distribution and opposing forces. Partner provides moderate resistance, using frames and attempting to stay on their side. Work on eliminating space and pinning shoulder blades to mat. Perform 10-15 repetitions per session.

Phase 3: Leg Extraction Timing (Weeks 5-6) - Learning when and how to extract trapped leg Once comfortable with flattening, add the leg extraction component. Partner is flattened but maintains light grip on your trapped leg. Practice the subtle hip movement and knee drive required to clear the leg while maintaining all upper body pressure. Focus on not creating space or lifting weight. 15-20 repetitions per session.

Phase 4: Full Pass Sequence (Weeks 7-8) - Completing entire pass from setup to side control consolidation Execute full passing sequence from initial underhook establishment through to secure side control. Partner provides moderate resistance, attempting to maintain half guard and prevent pass. Practice transitioning smoothly between all phases without losing pressure. Aim for 8-10 successful completions per session.

Phase 5: Counter Management (Weeks 9-10) - Dealing with common defensive responses and counters Partner actively attempts specific counters (underhook battle, knee shield, lockdown, turning to turtle). Practice recognizing and addressing each counter without losing position. Work on problem-solving in real-time while maintaining passing pressure. Focus on one counter type per session until comfortable with responses.

Phase 6: Live Integration (Week 11+) - Applying pass against full resistance in positional sparring Start in half guard top with goal of completing underhook pass. Partner provides full resistance using any legal defensive techniques. Time rounds (3-5 minutes) and track success rate. Focus on maintaining technical precision under pressure and recognizing optimal moments to initiate pass versus other passing options.

Safety Considerations

What are the safety concerns for Underhook Pass?

The underhook pass is generally a safe technique when executed properly, but practitioners should be aware of several safety considerations. Avoid driving excessive pressure into the opponent’s neck or head, as the crossface should target the chest and shoulder, not the cervical spine. When extracting the trapped leg, move methodically to avoid hyperextending your own or your opponent’s knee joints. Be cautious of cranking or twisting motions with the underhook that could stress the opponent’s shoulder joint. When drilling, partners should communicate about pressure levels, especially when learning the flattening mechanics. Beginners should focus on positional control rather than explosive movements that could result in knee or shoulder injuries.

Underhook Pass Attacker

Outcomes