Nirensei

Nirensei is an opening pattern in Go where a player places their first two stones on star points along the same side of the board. This formation emphasizes rapid development, flexibility, and influence over territory. While the shape itself is simple, its strategic potential is far-reaching, often leading to large-scale frameworks (moyo).

Historically, the nirensei pattern was rarely seen in even games until the 1930s, when Go Seigen and Kitani Minoru introduced it as part of the “New Fuseki” movement. Before that, its use was mostly limited to handicap games. Nirensei quickly gained popularity due to its speed and adaptability, becoming a staple of modern fuseki theory.

In professional play, when both players begin with nirensei on opposite sides of the board, it leads to symmetrical development and emphasizes whole-board strategy. However, with the rise of komi and AI-influenced playstyles, the pattern has become somewhat less favored at the top level, though it remains popular among amateurs for its clarity and strength.

Additional Notes

• If a third star point is added along the same side, the shape becomes a sanrensei (three star points in a row).
• The oldest known instance of nirensei in a non-handicap professional game is by Honinbo Shuwa in 1838.
• The pattern supports many follow-up strategies, including framework expansion, early attacks, or flexible responses to invasions.