{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,4]],"date-time":"2026-10-04T22:19:26Z","timestamp":1791152366147,"version":"4.1.0"},"reference-count":21,"publisher":"American Association for the Advancement of Science (AAAS)","issue":"5844","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Science"],"published-print":{"date-parts":[[2007,9,14]]},"abstract":"<jats:p>\n                    The game of checkers has roughly 500 billion billion possible positions (5 \u00d7 10\n                    <jats:sup>20<\/jats:sup>\n                    ). The task of solving the game, determining the final result in a game with no mistakes made by either player, is daunting. Since 1989, almost continuously, dozens of computers have been working on solving checkers, applying state-of-the-art artificial intelligence techniques to the proving process. This paper announces that checkers is now solved: Perfect play by both sides leads to a draw. This is the most challenging popular game to be solved to date, roughly one million times as complex as Connect Four. Artificial intelligence technology has been used to generate strong heuristic-based game-playing programs, such as Deep Blue for chess. Solving a game takes this to the next level by replacing the heuristics with perfection.\n                  <\/jats:p>","DOI":"10.1126\/science.1144079","type":"journal-article","created":{"date-parts":[[2007,7,19]],"date-time":"2007-07-19T21:10:48Z","timestamp":1184879448000},"page":"1518-1522","source":"Crossref","is-referenced-by-count":282,"title":["Checkers Is Solved"],"prefix":"10.1126","volume":"317","author":[{"given":"Jonathan","family":"Schaeffer","sequence":"first","affiliation":[{"name":"Department of Computing Science, University of Alberta, Edmonton, Alberta T6G 2E8, Canada."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Neil","family":"Burch","sequence":"additional","affiliation":[{"name":"Department of Computing Science, University of Alberta, Edmonton, Alberta T6G 2E8, Canada."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yngvi","family":"Bjo\u0308rnsson","sequence":"additional","affiliation":[{"name":"Department of Computing Science, University of Alberta, Edmonton, Alberta T6G 2E8, Canada."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Akihiro","family":"Kishimoto","sequence":"additional","affiliation":[{"name":"Department of Computing Science, University of Alberta, Edmonton, Alberta T6G 2E8, Canada."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Martin","family":"Mu\u0308ller","sequence":"additional","affiliation":[{"name":"Department of Computing Science, University of Alberta, Edmonton, Alberta T6G 2E8, Canada."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Robert","family":"Lake","sequence":"additional","affiliation":[{"name":"Department of Computing Science, University of Alberta, Edmonton, Alberta T6G 2E8, Canada."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Paul","family":"Lu","sequence":"additional","affiliation":[{"name":"Department of Computing Science, University of Alberta, Edmonton, Alberta T6G 2E8, Canada."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Steve","family":"Sutphen","sequence":"additional","affiliation":[{"name":"Department of Computing Science, University of Alberta, Edmonton, Alberta T6G 2E8, Canada."}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"221","reference":[{"key":"e_1_3_2_2_2","doi-asserted-by":"publisher","DOI":"10.1080\/14786445008521796"},{"key":"e_1_3_2_3_2","unstructured":"\u201cThe Duel: Man vs. Machine\u201d (www.rag.de\/microsite_chess_com)."},{"key":"e_1_3_2_4_2","doi-asserted-by":"crossref","unstructured":"J. Schaeffer One Jump Ahead (Springer-Verlag New York 1997).","DOI":"10.1007\/978-1-4757-2733-3"},{"key":"e_1_3_2_5_2","first-page":"12","volume":"14","year":"1999","unstructured":"M. Buro, IEEE Intell. Syst. J.14, 12 (1999).","journal-title":"IEEE Intell. Syst. J."},{"key":"e_1_3_2_6_2","unstructured":"B. Sheppard thesis Universiteit Maastricht Maastricht Netherlands (2002)."},{"key":"e_1_3_2_7_2","unstructured":"V. Allis thesis University of Limburg Maastricht Netherlands (1994)."},{"key":"e_1_3_2_8_2","doi-asserted-by":"publisher","DOI":"10.1016\/S0004-3702(01)00152-7"},{"key":"e_1_3_2_9_2","first-page":"26","volume":"36","year":"2003","unstructured":"J. Romein, H. Bal, IEEE Computer36, 26 (2003).","journal-title":"IEEE Computer"},{"key":"e_1_3_2_10_2","first-page":"108","volume":"237","year":"1977","unstructured":"K. Appel, W. Haken, Sci. Am.237, 108 (1977).","journal-title":"Sci. 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(Kluwer, Dordrecht, Netherlands, 2003), pp. 193\u2013210.","journal-title":"Advances in Computer Games"},{"key":"e_1_3_2_18_2","doi-asserted-by":"publisher","DOI":"10.1016\/0004-3702(75)90019-3"},{"key":"e_1_3_2_19_2","unstructured":"A. Nagai thesis University of Tokyo Japan (2002)."},{"key":"e_1_3_2_20_2","first-page":"644","year":"2004","unstructured":"A. Kishimoto, M. M\u00fcller, in Proceedings of the Nineteenth National Conference on Artificial Intelligence (AAAI Press, Menlo Park, CA, 2004) pp. 644\u2013649.","journal-title":"Proceedings of the Nineteenth National Conference on Artificial Intelligence"},{"key":"e_1_3_2_21_2","unstructured":"D. Beal thesis Universiteit Maastricht Maastricht Netherlands (1999)."},{"key":"e_1_3_2_22_2","unstructured":"The support of Canada's Natural Sciences and Engineering Research Council (NSERC) Alberta's Informatics Circle of Research Excellence (iCORE) and the Canada Foundation for Innovation is greatly appreciated. Numerous people contributed to this work including M. Bryant J. Culberson B. Gorda B. Knight D. Szafron K. Thompson and N. Treloar."}],"container-title":["Science"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.science.org\/doi\/pdf\/10.1126\/science.1144079","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2024,1,10]],"date-time":"2024-01-10T04:01:09Z","timestamp":1704859269000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.science.org\/doi\/10.1126\/science.1144079"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2007,9,14]]},"references-count":21,"journal-issue":{"issue":"5844","published-print":{"date-parts":[[2007,9,14]]}},"alternative-id":["10.1126\/science.1144079"],"URL":"https:\/\/doi.org\/10.1126\/science.1144079","relation":{},"ISSN":["0036-8075","1095-9203"],"issn-type":[{"value":"0036-8075","type":"print"},{"value":"1095-9203","type":"electronic"}],"subject":[],"published":{"date-parts":[[2007,9,14]]}}}