Butterfly

Butterfly—also called a Butterfly enclosure—is a specific two-stone corner enclosure arranged in a butterfly-like shape. The stones function together as one enclosure; the term describes the resulting configuration, not a single move.

Its purpose is to secure or claim the corner while establishing a base and developing potential influence toward the outside. Butterfly is one particular enclosure shape, whereas shimari is the general category of corner enclosures.

The shape is not automatically invulnerable. Its safety and value depend on surrounding stones, approach moves, and the timing of any invasion or reduction.