Monte Carlo tree search (MCTS) has been successfully applied to many games recently. Since then, many techniques are used to improve the strength of MCTS-based programs. This paper investigates four recent techniques: early playout terminations, implicit minimax backups, quality-based rewards and progressive bias. The strength improvements are analyzed by incorporating the techniques into an MCTS-based program, named DarkKnight, for Chinese Dark Chess. Experimental results showed that the win rates against the original DarkKnight were 60.75%, 71.85%, 59.00%, and 82.10%, respectively for incorporating the four techniques. The results indicated that the improvement by progressive bias was most significant. By incorporating all together, a better win rate of 84.75% was obtained.
['Chu-Hsuan Hsueh', 'I-Chen Wu', 'Wen-Jie Tseng', 'Shi-Jim Yen', 'Jr-Chang Chen']
An analysis for strength improvement of an MCTS-based program playing Chinese dark chess