Generalized Thermography: A New Approach To Evaluation in Computer Go

Martin Müller
Informatik, ETH Zürich

Go is a game of creating territories. Evaluation, or counting territory, is to a large extent a local process. Combinatorial game theory provides tools which are more efficient for localized analysis of games than full-board minimax search. One of these tools, thermography, has recently been generalized to local games that contain ko loops in their game graph.

Generalized thermography computes a mast value and a temperature for such games, which can be used to estimate the full board game score and the value of moves precisely.

We report the first implementation of an algorithm for generalized thermography, which can be used to evaluate almost arbitrary local Go positions. To illustrate the power and scope of our program, we give examples of ko positions and their thermographs.