ICGA Journal - Volume 36, issue 3

Article Type: Other

DOI: 10.3233/ICG-2013-36301

Citation: ICGA Journal, vol. 36, no. 3, pp. 129-130, 2013

Authors: Lin, Hung-Hsuan | Wu, I-Chen | Wei, Tinghan

Article Type: Research Article

Abstract: Since Sudoku was invented, it has been interesting to find Sudoku puzzles with the minimum number of clues. Royle collected 49,151 17-clue Sudoku puzzles between 2005 and 2009, each of which is not isomorphic to any other, and McGuire claimed in 2012 that no 16-clue Sudoku puzzle exists. Since 2009, no new 17-clue Sudoku puzzles have been found. This paper proposes an algorithm to find 17-clue Sudoku puzzles based on the number of clues in the topmost 9x3 cells, which is called a top-block. Using this algorithm, we prove that (1) no 17-clue puzzles exist of which the top-block has …fewer than three clues and (2) precisely 95 17-clue puzzles exist of which the top-block has three and only three clues. Moreover, we compared these 95 puzzles to the 49,151 collected 17-clue Sudoku puzzles and found that these 95 puzzles are already collected by Royle. Thus, a conjecture from this paper is that most of the 17-clue Sudoku puzzles have been found. Show more

DOI: 10.3233/ICG-2013-36302

Citation: ICGA Journal, vol. 36, no. 3, pp. 131-138, 2013

Authors: Nunn, John

Article Type: Research Article

Abstract: The 7-man MVL endgame tablebases from the Lomonosov team are now available online. This note discusses some discoveries made on revisiting the R+2P vs R+P positions in the book Rook Endings by Levenfish and Smyslov. It addresses the accuracy rate of top-level pre-computer analysis and explores the types of finesse overlooked by even expert players. Counter-intuitive ideas are shown to be relatively common in this type of ending.

DOI: 10.3233/ICG-2013-36303

Citation: ICGA Journal, vol. 36, no. 3, pp. 139-142, 2013

Authors: Haworth, G.McC.

Article Type: Research Article

DOI: 10.3233/ICG-2013-36304

Citation: ICGA Journal, vol. 36, no. 3, pp. 143-145, 2013

Authors: Kirchhof, Klaus

Article Type: Research Article

Abstract: A programmer’s analysis of the problem is presented. The total number of solutions is listed.

DOI: 10.3233/ICG-2013-36305

Citation: ICGA Journal, vol. 36, no. 3, pp. 146-149, 2013

Article Type: Other

DOI: 10.3233/ICG-2013-36306

Citation: ICGA Journal, vol. 36, no. 3, pp. 150-150, 2013

Authors: Krabbenbos, Jan | Haworth, Guy | van den Herik, Jaap

Article Type: Other

DOI: 10.3233/ICG-2013-36307

Citation: ICGA Journal, vol. 36, no. 3, pp. 151-158, 2013

Authors: Krabbenbos, J. | van den Herik, H.J.

Article Type: Other

DOI: 10.3233/ICG-2013-36308

Citation: ICGA Journal, vol. 36, no. 3, pp. 158-158, 2013

Authors: Krabbenbos, Jan | Haworth, Guy | van den Herik, Jaap

Article Type: Other

DOI: 10.3233/ICG-2013-36309

Citation: ICGA Journal, vol. 36, no. 3, pp. 159-165, 2013

Authors: Tseng, Wen-Jie | Chen, Jr-Chang | Chen, Lung-Ping | Yen, Shi-Jim | Wu, I-Chen

Article Type: Other

DOI: 10.3233/ICG-2013-36310

Citation: ICGA Journal, vol. 36, no. 3, pp. 166-168, 2013