Dynamic play via suit factorization search in skat

Abstract

In this paper we look at multi-player trick-taking card games that rely on obeying suits, which include Bridge, Hearts, Tarot, Skat, and many more. We propose mini-game solving in the suit factors of the game, and exemplify its application as a single-dummy or double-dummy analysis tool that restricts game play to either trump or non-trump suit cards. Such factored solvers are applicable to improve card selections of the declarer and the opponents, mainly in the middle game, and can be adjusted for optimizing the number of points or tricks to be made. While on the first glance projecting the game to one suit is an over-simplification, the partitioning approach into suit factors is a flexible and strong weapon, as it solves apparent problems arising in the phase transition of accessing static table information to dynamic play. Experimental results show that by using mini-game play, the strength of trick-taking Skat AIs can be improved.