Life in the game of Go

The Oriental game of Go contains a unique method by which pieces, called stones, are captured and made safe from capture. A group of stones safe from capture is called safe, unconditionally alive, or similar terms. Life or its lack can be determined by lookahead through the game tree, at some expense. We present a graph-theoretic static analysis of the board arrangement which determines unconditional life or its lack, together with proofs of its equivalency to look ahead. An algorithm for the static evaluation is given and we argue that it is the preferable method for computer Go play. These results constitute the first realistic theorems in the theory of Go.