Oki

Oki is a tactical play where a stone is placed inside the opponent’s area, without directly touching other stones. Such placements can serve a range of purposes—killing a group, creating a false eye, reducing territory in the endgame (yose), or even acting as a sacrifice to gain sente.

This type of move often targets the vital point of a group and can lead to unexpected turnarounds. Despite its boldness, an oki can also fail if misread, turning into a speculative invasion that gives the opponent strength.