Half Guard to Jailbreak is a 10th Planet entry in which the bottom half guard player secures a same-side underhook and turns into an inverted setup, converting the top player’s forward crossface pressure into the Jailbreak escape junction.
Half Guard to Jailbreak is the entry that lands a flattened bottom half guard player into the Jailbreak position, the dynamic 10th Planet escape junction. Rather than grinding for a traditional knee-shield or frame recovery, the bottom player accepts the top player’s forward pressure as fuel: they win or maintain the same-side underhook, tuck the chin, and turn their shoulders toward the trapped-leg side to load the explosive inversion.
The entry is fundamentally a baiting and timing exchange. A skilled passer wants to flatten the half guard bottom player with a heavy crossface and drive their weight forward to complete the pass. The Jailbreak entry uses that exact forward commitment - the moment the passer’s center of gravity advances over a narrow base is the moment the underhook-and-invert becomes mechanically viable. The bottom player is not trying to sweep or recover guard in this single action; they are arriving at the Jailbreak junction from which the explosive roll, deep half dive, or back take then unfolds.
Because it trades the relative safety of a framed half guard for a committed, dynamic position, the entry carries real risk: if the underhook is lost or the timing is early, the passer can flatten the bottom player completely and finish the pass to side control. Executed against forward pressure with a tight underhook and tucked chin, however, it is one of the most reliable ways for a modern no-gi guard player to turn a losing flattened half guard into an active offensive scramble.
From Position: Half Guard (Bottom) Success Rate: 55%
Possible Outcomes
| Result | Position | Probability |
|---|---|---|
| Success | Jailbreak | 55% |
| Failure | Half Guard | 30% |
| Counter | Side Control | 15% |
Attacker vs Defender
| Attacker | Defender | |
|---|---|---|
| Focus | Execute technique | Prevent or counter |
| Key Principles | Win and keep the same-side underhook - it is the structural … | Control or strip the same-side underhook early - without it … |
| Options | 6 execution steps | 3 defensive options |
Playing as Attacker
Key Principles
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Win and keep the same-side underhook - it is the structural fulcrum that lets you arrive at the Jailbreak with control rather than getting flattened
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Use the passer’s forward pressure as fuel: enter when their weight commits over a narrow base, not when they are sitting back and based wide
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Tuck the chin and round the shoulders before inverting to protect the neck and enable a smooth granby-style turn
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Turn toward your trapped-leg side so your hips and shoulders rotate as a connected unit into the inversion
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Stay connected with elbow-to-hip on the underhook side so the passer cannot peel you off as you turn
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Treat this as an arrival, not a finish - your goal is to reach the Jailbreak junction loaded, then choose roll, back take, or deep half
Execution Steps
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Win the same-side underhook: From bottom half guard, drive your underhook arm deep under the opponent’s same-side armpit (the sid…
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Bait or read the forward pressure: Invite the passer to commit by giving them a flatter-looking target, or simply read the moment they …
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Tuck the chin and round the shoulders: As you feel the forward weight, tuck your chin hard toward your chest and round your upper back. Thi…
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Turn toward your trapped-leg side: Rotate your hips and shoulders together toward the side of your trapped leg, keeping the underhook e…
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Post the free leg and load the inversion: Drive your free (non-trapped) foot into the mat and use it to push your hips up and over, beginning …
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Arrive at the Jailbreak junction: With the underhook held, chin tucked, and shoulders inverting, you have now reached the Jailbreak po…
Common Mistakes
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Turning in without first securing the underhook
- Consequence: You expose your back and neck; the passer takes the back or flattens you straight to side control.
- Correction: Always win and glue the same-side underhook (elbow to hip) before you begin the turn. No underhook, no Jailbreak entry.
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Entering against a wide, seated passing base
- Consequence: There is no forward weight to convert into rotation, so the turn stalls and you get smashed flat.
- Correction: Wait for, or bait, the passer’s forward weight commitment. If they stay based wide, switch to deep half instead of forcing the Jailbreak.
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Failing to tuck the chin during the inversion
- Consequence: The roll loads your cervical spine, risking neck injury and stalling the motion mid-turn.
- Correction: Tuck the chin to your chest and look at your own belt before and during the turn. Protect the neck first, then invert.
Playing as Defender
Key Principles
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Control or strip the same-side underhook early - without it the bottom player cannot safely turn into the Jailbreak
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Pass with a wide, heavy base; do not over-commit weight forward over a narrow base that feeds their rotation
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Recognize the chin tuck and turn-toward-trapped-leg as the entry signal and react before the inversion loads
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When they turn in, threaten their exposed back rather than passively following the roll
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Switch your hips and widen your base to deny the rolling momentum if you cannot strip the underhook in time
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Prioritize completing the pass to side control over chasing a low-percentage submission as they turn
Recognition Cues
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The bottom player digs hard for a deep same-side underhook and pulls their elbow tight to their own hip
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The bottom player tucks their chin to their chest and rounds their shoulders rather than framing to push you away
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The bottom player begins rotating their hips and shoulders toward their trapped-leg side as you drive forward
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You feel your forward weight suddenly being absorbed and redirected into a turning, corkscrewing motion beneath you
Defensive Options
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Strip or limp-arm the underhook and re-flatten before they can turn - When: Earliest recognition - when they are still digging for or have just won the underhook but have not yet tucked and turned
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Widen your base and switch your hips to deny the rolling momentum - When: Mid-entry - when they have begun the turn and you cannot strip the underhook in time
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Follow the turn to chase their exposed back - When: When they fully commit to the inversion and their back briefly turns toward you
Position Integration
Half Guard to Jailbreak is the primary on-ramp into the 10th Planet Jailbreak escape system from one of grappling’s most common losing spots - flattened bottom half guard. It sits at the junction of the underhook half guard game: the same same-side underhook that drives the old school sweep and the deep half dive also powers this entry, and the passer’s response (forward weight versus wide base) determines which of those paths opens. Strategically, the entry reframes a defensive crisis as an offensive scramble, connecting the static half guard battle to the dynamic Jailbreak outcomes of roll-to-turtle, back take, and deep half. Mastering it gives the bottom player a reliable answer to heavy pressure passing in modern no-gi, where flattened half guard would otherwise lead directly to a pass.