Extension

An extension places a stone at a point extending from an existing friendly stone or group, usually along a side or toward open space. Its distance and direction depend on nearby stones, the board edge, and tactical threats. It may be adjacent to the friendly stones or leave one or more spaces between them.

Extensions can develop a group, enlarge potential territory, gain influence, establish a base, or reduce the opponent’s room to approach or invade. An extension is a general positional move away from friendly stones; a one-space jump and other jumps leave a gap and are identified by their specific movement pattern. A checking extension also threatens or restricts an opposing group. An extension is not automatically secure: if it is too far or lacks sufficient support, the opponent may attack, cut, or invade.