Abstrakt
We present a state of the art implementation of the Monte Carlo Tree Search algorithm for the game of Go. Our "Pachi" software is currently one of the strongest open source Go programs, competing at the top level with other programs and playing evenly against advanced human players.
We describe our implementation and choice of published algorithms as well as some notable original improvements: an adaptive time control algorithm, dynamic komi, and usage of the criticality statistic. We also present new methods to achieve efficient scaling both in terms of multiple threads and multiple machines in a cluster.