Nirensei

Nirensei is a Go opening formation in which two stones occupy star points in a row, usually two adjacent hoshi points along one side of the board. Also called the Two-star opening, it establishes a framework with influence toward the side and center while leaving the corners relatively open for subsequent play.

The formation develops influence and potential territory efficiently, while retaining flexibility for further extension, approach, invasion, or enclosure. Unlike sanrensei, which extends the same basic arrangement to three star points, nirensei uses two aligned star-point stones. It is a starting pattern rather than a fixed strategy: its value depends on the moves that follow and on the surrounding positions.