Last update August 1, 2006

Technical Report #207

 


Effective Use of Expensive Evaluation Function and Design of Directional Asymmetric Orientation Evaluation Function for Shogi

 

T. Hamada, T. Hashimoto and H. Iida

Abstract. Search and position evaluation are the cores for developing a computer shogi.  Expensive evaluation function that considers the influence of the major piece attack cannot easily be called. This paper verifies an appropriate range on a method to improve search efficiency not by calling such an expensive position evaluation in case where there are some large margins with alpha or beta value. Moreover, it proposes a new design of expensive but high-quality position evaluation based on Directional Asymmetric Orientation. The implementation task is not so difficult if all directions are equally evaluated. Nevertheless, it is inadequate in many cases. Examining only the important directions enables the position evaluation more accurate. We then implement ¡£¥Íshort range pieces in the opponent zone¡£¥Î and ¡£¥Ímajor piece mobility¡£¥Î as evaluation factor based on Directional Asymmetric Orientation.

This paper was presented at 10th Game Programming Workshop, November 18-20, 2005, Hakone, included in the Proceedings, IPSJ, Symposium Series Vol.2005, No.15. ISSN: 1344-0640

 

 

 


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