Reduction

A reduction is a move played within, or near the edge of, an opponent’s moyo or potential territory. Its aim is to reduce the framework’s size and territorial value. The reducing stone usually remains relatively shallow, retaining an option to escape or run while limiting the opponent’s outward development.

The purpose is to diminish the opponent’s territorial potential and influence while avoiding the greater risks of a deep invasion. Unlike an invasion, a reduction generally does not try to establish a group deep inside the framework; it restricts the framework from a safer distance. The stone still needs sufficient room to escape, and the appropriate timing and depth depend on the surrounding position and on the opponent’s potential attack.