Back Triangle — No-Gi Grappling

What This Is

The back triangle is a leg-based strangle applied from back control. The attacker’s legs lock in a triangle figure-four around the opponent’s neck and one arm — the same geometry as a standard guard triangle, applied from behind. The submission compresses both carotids through thigh pressure: one thigh on each side of the neck.

This submission is distinct from the rear triangle (SUB-TRI-REAR). In the back triangle, the legs wrap around the neck and near arm while the attacker is behind the opponent in back control position. In the rear triangle, the legs wrap around the neck from a different angle — from north-south or a high back position — without the near arm being inside the triangle. They are mechanically related but structurally distinct.

The back triangle emerges from seatbelt control in a specific way: the strangle arm of the seatbelt becomes the frame for the triangle entry. It is typically used when the RNC is being defended by a sustained chin tuck that cannot be solved through direct entry — the chin tuck that blocks the forearm from the throat also positions the arm in a way that creates triangle entry geometry.

Finishing: the hips thrust forward while the triangle squeeze is applied. The thighs compress both sides of the neck. The arm inside the triangle should stay close to the neck — tightening the near-side compression. This is the same arm-in triangle principle that applies in standard guard triangles.

The Invariable in Action

The back triangle’s bilateral compression is achieved through the thighs. One thigh compresses the carotid on the arm-in side; the other thigh compresses the carotid on the free side. The arm inside the triangle increases the near-side compression by being pressed against the neck. This is why the arm-in position is critical — without the arm inside the triangle, the near-side thigh cannot compress both carotid and arm simultaneously, and the submission may be one-sided.

The arm-in principle: the near arm must be captured inside the triangle. If the arm escapes outside the triangle, the near-side thigh loses compression on the carotid because the arm is no longer pressing it inward. The arm must be kept inside — controlled by the leg position and, if necessary, by the attacker’s hand gripping the arm and pulling it into the neck. This is a common adjustment required mid-finish.

"Establishing connection is the prerequisite for all control. Where INV-01 describes what sustained connection achieves, INV-07 describes the prior requirement: control cannot begin until connection exists. Distance — whether created by the opponent deliberately or allowed to develop accidentally — returns initiative to the opponent and must be closed before control can be re-established."

Why it works here

The leg swing from hooks to the triangle requires a brief window where the hook releases — during that window the seatbelt grip is the only retention mechanism. A loose seatbelt during the transition lets the opponent rotate and face out before the triangle locks. The grip must be tightest at the moment the hook leaves the thigh, not after the legs arrive at the neck.

See full invariable page →

The transition from hooks to triangle requires a brief window in which the hook is released and the leg swings to the neck. During this window, the back position must be maintained by the seatbelt grip alone. If the seatbelt grip is loose during the transition, the opponent can use the hook release to begin rotation and face out.

Defence

Arm extraction: The primary defence is extracting the arm from inside the triangle before the triangle is locked. Once the triangle is fully locked, arm extraction is very difficult. The window for extraction is during the transition phase, before the locking leg’s ankle is hooked behind the knee. If the arm can be pulled to the outside of the triangle as the legs are locking, the triangle loses the arm-in compression.

Stack: If the triangle is locked, stacking the opponent — driving weight through the triangle to compress it — may temporarily relieve pressure and allow the arm to move. This is a high-commitment defence that typically requires technical follow-up to escape.

Posture: Extending the neck (chin up) in a standard guard triangle helps defend; in the back triangle, this is less available because the attacker is behind and can use their body position to drive the head forward. The chin tuck — which defends the RNC — paradoxically assists the back triangle by keeping the head in position. Defending one creates an opening for the other.

Setup and Entry

From Seatbelt — RNC to Back Triangle Transition

This is the most common entry and the most important one to understand because it connects the back triangle directly to the RNC defence.

When the opponent has a sustained chin tuck that prevents the RNC forearm from entering the throat: the strangle hand (which is blocked at the chin) creates the entry frame for the triangle. Instead of continuing to fight the chin, the attacker uses the strangle arm as the near-side triangle frame and swings the near leg (the hook on the strangle arm side) up and over the opponent’s shoulder, toward the neck. The leg passes behind the opponent’s head. The far leg then hooks behind this leg’s ankle (or knee, depending on the configuration), creating the triangle figure-four. The strangle arm guides the opponent’s near arm into the inside of the triangle during this process.

The entry requires coordination between the arm guiding and the leg swinging — both happen simultaneously. Practising the arm guide without the leg swing, and the leg swing without the arm guide, before combining them is the recommended drilling sequence.

Direct Entry from Body Triangle

From body triangle, the leg configuration is already partially in place. One leg wraps the waist; transitioning the upper leg from the figure-four to the neck is the movement. This is a less common direct entry but available from a body triangle that has migrated upward.

Position Requirements

Seatbelt Control (POS-BACK-TOP-SEATBELT) — Primary. The strangle arm provides the triangle frame; the hook transitions to the leg swing. Highest reliability.
Body Triangle (POS-BACK-TOP-BODYTRI) — Available via leg migration from body triangle. Less direct than from seatbelt with hooks but available from the upper leg position.

Common Errors

Error 1: Allowing the arm to escape to the outside during the triangle entry

Why it fails: If the near arm escapes outside the triangle as the legs are locking, the triangle loses bilateral compression. The submission becomes one-sided. The arm guide — using the strangle hand to keep the near arm inside — must be active during the entire leg transition.

Correction: The strangle arm’s job during the back triangle entry is to guide the near arm inside the triangle’s path. The arm guide and the leg swing are one simultaneous action.

Error 2: Squeezing before the triangle is fully locked

Why it fails: Squeezing before the ankle is hooked behind the knee allows the opponent to pull their head out or create enough space to escape the leg position. The triangle must be fully locked before finishing pressure is applied.

Correction: Confirm the ankle-behind-knee lock before beginning the squeeze. The lock should feel tight and rigid, with no space at the neck, before the hips thrust forward.

Error 3: Losing the seatbelt grip during the leg swing

Why it fails: The leg swing from hook to neck requires releasing the hook. During this moment, the seatbelt grip is the only back control. If the grip is loose, the opponent can rotate. The grip must be tight and the movement fast.

Correction: Tighten the seatbelt grip before initiating the leg swing. The grip should be at its tightest during the transition, not relaxed to free the leg.

Drilling Notes

Systematic Drilling

Drill the arm guide and the leg swing separately first. For the arm guide: from seatbelt, practice using the strangle arm to pull the near arm inside a simulated triangle path. For the leg swing: from seatbelt, practice swinging the near leg up and over the shoulder without the arm guide. Combine them once both movements are individually reliable. Then add the triangle lock and finish.

Ecological Drilling

Positional sparring from RNC attempt — when the chin is tucked and the RNC forearm is blocked, transition to the back triangle. This connects the back triangle to its natural entry context and prevents it from being drilled as a standalone technique that never appears in live grappling.

Ability Level Guidance

Proficient

Learn the back triangle as the secondary submission to the RNC — the technique used when the chin defence is holding. Drill the transition between the two so they form a system rather than two isolated attempts. The practitioner who can threaten both creates a dilemma the opponent cannot fully resolve with a single defence.

Advanced

Study the back triangle as a primary attack in its own right. The back triangle can be the first submission attempted rather than the fallback. The threat of the back triangle creates openings for the RNC — the opponent’s response to the triangle entry may expose the throat. Use both directions of the threat relationship.

Also Known As

Also known as

Back body triangle(Distinguishes from the rear triangle — not always consistently applied)
Arm-in back choke(Descriptive term used in some competition contexts)