ICGA Journal - Volume 30, issue 1

Authors: van den Herik, Jaap

Article Type: Other

DOI: 10.3233/ICG-2007-30101

Citation: ICGA Journal, vol. 30, no. 1, pp. 1-2, 2007

Authors: Ciancarini, Paolo | Favini, Gian Piero

Article Type: Research Article

Abstract: The game of Kriegspiel is a variant of the game of Chess. Kriegspiel is interesting because most chess rules are still valid, but gameplay is characterized by incomplete information as players may not see their opponent’s pieces and can only try to guess their positions by listening to the messages of a referee. We describe a Kriegspiel-playing program based on the concept of metaposition , that is, the merging of a rather large set of possible game states into a single entity. This merging operation allows us to exploit traditional perfect-information game-theory tools, such as the Minimax theorem. We …provide a general representation of Kriegspiel states through metapositions and describe an algorithm for building and exploring a game tree of metapositions. Our method does not assume that the opponent will react with a best defence model. We have evaluated our approach by competing against both human and computer players. Show more

DOI: 10.3233/ICG-2007-30102

Citation: ICGA Journal, vol. 30, no. 1, pp. 3-24, 2007

Authors: Grimbergen, Reijer

Article Type: Research Article

Abstract: In this paper it will be explained how to use bitboards for move generation in shogi. In chess, bitboards have been used in most strong programs because of the easy representation of a chess board by a single 64-bit integer. For shogi, a less efficient representation has to be used because a shogi board has 81 squares instead of 64. A representation with an array of three integers is proposed, where each integer represents 27 squares of the board. This representation is then used for move generation in a similar way to the methods used in chess, for example by …using rotated bitboards for generating the moves of the sliding pieces Rook and Lance. For generating the moves of the Bishop, rotated bitmaps are not completely satisfactory and a different method using the alignment of diagonals is proposed for move generation. A comparison of the move-generation speed between using bitboards and the more common method of using attack tables showed that even without using hardware-dependent optimizations the move-generation speed of the shogi program SPEAR using bitboards was more than 40% faster than the move generation using attack tables. Show more

DOI: 10.3233/ICG-2007-30103

Citation: ICGA Journal, vol. 30, no. 1, pp. 25-34, 2007

Authors: Cazenave, Tristan

Article Type: Research Article

Abstract: Playing the right atari is an intriguing heuristic that can be used for a powerful optimization of Monte-Carlo Go tree search. It consists in dealing appropriately with strings that have two liberties. The heuristic is contained in one page of code and the Go program that uses it improves from 50 per cent of won games against GNU Go 3.6 to 76 per cent of won games.

DOI: 10.3233/ICG-2007-30104

Citation: ICGA Journal, vol. 30, no. 1, pp. 35-42, 2007

Authors: Schadd, Maarten P.D. | Winands, Mark H.M. | Bergsma, Maurice H.J. | Uiterwijk, Jos W.H.M. | van den Herik, H. Jaap

Article Type: Research Article

DOI: 10.3233/ICG-2007-30105

Citation: ICGA Journal, vol. 30, no. 1, pp. 43-44, 2007

Authors: Hartmann, Dap

Article Type: Book Review

DOI: 10.3233/ICG-2007-30106

Citation: ICGA Journal, vol. 30, no. 1, pp. 45-47, 2007

Article Type: Other

DOI: 10.3233/ICG-2007-30107

Citation: ICGA Journal, vol. 30, no. 1, pp. 48-48, 2007

Authors: Kaufman, Larry

Article Type: Other

DOI: 10.3233/ICG-2007-30108

Citation: ICGA Journal, vol. 30, no. 1, pp. 49-52, 2007

Authors: Scheuschner, Tobias

Article Type: Other

DOI: 10.3233/ICG-2007-30109

Citation: ICGA Journal, vol. 30, no. 1, pp. 52-54, 2007

Authors: van Reek, J. | Uiterwijk, J.W.H.M.

Article Type: Other

DOI: 10.3233/ICG-2007-30110

Citation: ICGA Journal, vol. 30, no. 1, pp. 54-56, 2007