IHH

IHH is the universal grappling abbreviation for the inside heel hook — the rotational leg-lock submission that loads the knee complex through rotation applied to the heel from inside the leg-entanglement position.

Etymology. The abbreviation expands to “inside heel hook” and parallels OHH (outside heel hook), the abbreviation pair for the two rotational directions of the heel hook family. The shorthand IHH emerged in modern submission-grappling and no-gi instructional vocabulary as the leg-entanglement era formalised position-and-attack labels; the abbreviation predominates in submission-only ruleset commentary and the social-media post-match descriptions (“won by IHH at 4:18”). The inside variant became the central submission of the modern leg-locking era, with submission-only and ADCC competition shifting its acceptance from “dirty” to “primary attack” in the 2010s.

Mechanics. The configuration applies rotational load to the heel from inside the leg-entanglement structure (typically cross-ashi or inside sankaku), driving the foot in the direction that loads the knee through internal rotation past its structural limit. Inside-space control is the prerequisite — without the inside hook orienting the heel correctly, the rotation cannot reach the knee’s failure point.

Cross-reference. Full term is “inside heel hook.” The outside variant is “outside heel hook” or “OHH.” Full mechanical coverage on Inside Heel Hook.