Alias · Guard
Half butterfly
Also known as Butterfly Guard — the canonical term used on this site.
Training background: when one hook is in — a transitional variant
Half-butterfly as a one-hook butterfly guard
Half butterfly, in this sense, is a name for a single-hook variant of butterfly guard — one butterfly hook in play rather than two.
Etymology. “Half butterfly” describes butterfly guard with only one hook inserted, often hybridised with half guard. The term also names a half-guard passing context elsewhere; here it refers to the butterfly guard it derives from. The “half” marks the single active hook.
Mechanics. Even with one hook, the guard works through hip mobility: the single butterfly hook under the thigh elevates and off-balances the passer when the hips drive into it, so the bottom player threatens the same sweeps as full butterfly from the one active hook by keeping the hips mobile beneath it.
Cross-reference. Full mechanical coverage on Butterfly Guard.