Joseki

In go and shogi, a joseki or jouseki (定石 jōseki for go, 定跡 for shogi) is the studied sequences of moves for which the result is considered balanced for both black and white sides.

In go, because games typically start with plays in the corners, go josekis are usually about corner play as the players try to gain local advantages there in order to obtain a better overall position. Though less common, there are also josekis for the middle game. In Japanese, 定 (jō) means "fixed" or "set" and 石 (seki) means stones, giving the literal meaning "set stones", as in "set pattern". In Chinese, the term for joseki is 定式, dìngshì.

The concept of "balance", here, often refers to an equitable trade-off between securing territory in the corner versus making good thickness toward the sides and the center. In application, these concepts are very dynamic, and, often, deviations from a joseki depend upon the needs of the situation and the available opportunities. While learning joseki is a tool to defend against a local loss, players always seek to take advantage of weaknesses in the opponent's shapes, often deviating from the joseki.

Josekis are not fixed but comprise patterns that have gained acceptance in professional games; they constitute a consensus that may change with certain caveats. Hence, the basic definition may be misleading for new players in that a joseki can be misconstrued as foolproof and unalterable and as optimal for all situations. Many josekis are in fact useful only for study within an artificially confined corner, and in real play are only considered good form when used in proper combination with other plays on the board (i.e. other joseki and fuseki moves).

Knowing a particular joseki simply means that one knows a sequence of moves, resulting in a balance or fair trade-off between black and white positions. This is in practice much easier than appraising how josekis relate to the rest of the board – hence, knowledge of joseki is regarded as shallow, when compared with the ability to integrate a strategy into a complex game landscape.

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Wikipedia