Glossary /// Alias
Gyaku sankaku defence
Also known as Reverse Triangle Escape — the canonical term used on this site.
Japanese — gyaku (reverse) sankaku (triangle)
Gyaku sankaku defence is the judo-derived name for defending the reverse triangle — the inverted-orientation triangle in the five-triangle classification.
Etymology. Gyaku means “reverse” and sankaku means “triangle”. ⚠ The name matters here because the family’s Japanese terms are routinely swapped: hantai belongs to the opposite triangle and ushiro to the rear, and this site carried the hantai label on the reverse triangle until the SS-3/4 accuracy pass corrected it.
Mechanics. The attacker’s outside leg swings over the shoulder and the inside leg tucks underneath. The defender’s own trapped shoulder supplies one side of the compression, which is why recovering that arm collapses the lock more reliably than fighting the legs.
Cross-reference. Full escape coverage on Reverse Triangle Escape.