Z-Lock
The Z-lock is a hip submission — the only submission in the lower limb system that targets the hip joint rather than the knee
Adapted from InGrappling, Z-Lock. System Games did not invent this curriculum.
FamilyLeg LocksLevelAdvancedPerspectiveTopIntentOffensiveSafetyElevatedHubLeg EntanglementsMapView on graph →This technique has elevated risk. Make sure you've covered the prerequisites before attempting.
Manage injuries →Position map Connects to 6 positions across 3 relationshipsOpen in the map →123456←Attacked from
The Z-lock is the only submission in the lower limb system that targets the hip joint. Every other leg lock targets the knee or ankle — the Z-lock attacks the hip through a specific rotational force that is only accessible from diagonal ashi garami. The position creates the submission; no other leg entanglement provides the correct attack angle.
The hip is a ball-and-socket joint with substantial natural range. Attacking it requires a very specific angle that loads the labrum and the joint capsule at the end of combined external rotation and extension — a configuration the hip does not reach in normal movement. This is not an incidental position: diagonal ashi garami was developed precisely because it creates this angle.
Because the Z-lock targets a different joint family from heel hooks and ankle locks, it requires different positional knowledge and different defensive awareness. Many grapplers training heel hook defence have no developed awareness of hip submission threats. This is part of what makes the Z-lock a credible threat at high levels — it attacks a structure that is not conventionally defended.
Elevated RiskZ-Lock is an elevated risk technique. The Z-lock loads the hip joint capsule and labrum through rotational force at the end of the joint's range. Hip labral tears and capsular damage are possible. The hip has a slower feedback signal than the knee — the submission can progress further before pain registers acutely. Serious injury can occur slower signal than knee submissions — but damage can occur before acute pain.
If you are new to this technique: read this section before anything else. Understanding the danger is part of understanding the technique.
The person applying the technique is responsible for releasing immediately.