joseki

In Go, joseki are locally optimal sequences of moves in the corner that arise from the interaction of early corner stones, such as the 4-4, 4-3, or 3-3 patterns. A joseki describes a defined course of play intended to settle the local fight and to secure a balanced outcome for both players over the next several moves.

The purpose of joseki is to help players resolve a corner efficiently while developing useful shapes and influence for the rest of the board. They are built on conventional patterns and are evaluated for local profit, not global victory. Because the surrounding position and global strategy vary, players often adapt or abandon a joseki when it would give the opponent a better overall position.

There are many joseki families, with dozens of variations. Some lead to solid territory for one side, others to influence and thickness. The effectiveness depends on the context, komi, and later moves on the board; modern players study joseki as a tool, not a rigid prescription.

Historically, joseki originated in Japan and have since spread worldwide. The name is from Japanese 定石, literally "established sequence" or "settled stones". In the modern era, AI and high-level play have added new lines and challenged traditional sequences, but joseki remain a foundational concept in opening study.