CHECKING LIFE-AND-DEATH PROBLEMS IN GO I: THE PROGRAM SCANLD 1

Abstract

In this article we introduce the program SCANLD (built on GOTOOLS) which checks solutions of life-and-death problems for correctness. It is a task for which computer programs are especially useful. They do the computations, they also do the handling of data in checking all moves of all solutions for optimality, and they report any errors that occur. Their refutation and their correction would be tedious and error prone if done with a computer, but interactively.

After discussing the different types of checks that are performed and giving some statistics resulting from checking a 500-problem tsume-go book, some examples are given. A detailed list of mistakes that have been found is given in an on-line addendum to the article.