Hantaisankaku

Hantaisankaku is the judo name for the opposite triangle — the triangle configuration with the figure-four locked on the reversed side relative to the trapped arm.

Etymology. Hantai (反対) means “opposite”; sankaku (三角) means “triangle.” The combined term names the member of the five-triangle classification whose lock sits on the opposite side from the standard front triangle: the same head-and-arm capture, but the choking knee on the wrong side relative to the trapped arm. The term appears in legacy judo literature and survives in modern no-gi vocabulary through the five-triangle taxonomy.

Mechanics. Because the choking leg’s calf does not cross the carotid line, the strangle from this lock is hard to complete. The configuration’s real value is as a trapping position and armlock platform — the kimura, americana and straight armlock on the trapped arm are directly available — with the strangle recovered by re-locking to the front triangle.

Cross-reference. English-speaking no-gi uses “opposite triangle” or “opposite-side triangle.” Full mechanical coverage on Opposite-Side Triangle.