Computer Analysis of World Chess Champions1

Who is the best chess player of all time? Chess players are often interested in this question that has never been answered authoritatively, because it requires a comparison between chess players of different eras who never met across the board. In this contribution, we attempt to make such a comparison. It is based on the evaluation of the games played by the World Chess Champions in their championship matches. The evaluation is performed by the chess-playing program CRAFTY. For this purpose we slightly adapted CRAFTY. Our analysis takes into account the differences in players' styles to compensate the fact that calm positional players in their typical games have less chance to commit gross tactical errors than aggressive tactical players. Therefore, we designed a method to assess the dif culty of positions. Some of the results of this computer analysis might be quite surprising. Overall, the results can be nicely interpreted by a chess expert.