{"action":"created","issue":{"url":"https://api.github.com/repos/official-stockfish/Stockfish/issues/925","repository_url":"https://api.github.com/repos/official-stockfish/Stockfish","labels_url":"https://api.github.com/repos/official-stockfish/Stockfish/issues/925/labels{/name}","comments_url":"https://api.github.com/repos/official-stockfish/Stockfish/issues/925/comments","events_url":"https://api.github.com/repos/official-stockfish/Stockfish/issues/925/events","html_url":"https://github.com/official-stockfish/Stockfish/pull/925","id":195330912,"number":925,"title":"Threefold repetition detection","user":{"login":"saproj","id":15147381,"avatar_url":"https://avatars.githubusercontent.com/u/15147381?v=3","gravatar_id":"","url":"https://api.github.com/users/saproj","html_url":"https://github.com/saproj","followers_url":"https://api.github.com/users/saproj/followers","following_url":"https://api.github.com/users/saproj/following{/other_user}","gists_url":"https://api.github.com/users/saproj/gists{/gist_id}","starred_url":"https://api.github.com/users/saproj/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/saproj/subscriptions","organizations_url":"https://api.github.com/users/saproj/orgs","repos_url":"https://api.github.com/users/saproj/repos","events_url":"https://api.github.com/users/saproj/events{/privacy}","received_events_url":"https://api.github.com/users/saproj/received_events","type":"User","site_admin":false},"labels":[],"state":"open","locked":false,"assignee":null,"assignees":[],"milestone":null,"comments":49,"created_at":"2016-12-13T18:26:57Z","updated_at":"2016-12-20T13:34:08Z","closed_at":null,"pull_request":{"url":"https://api.github.com/repos/official-stockfish/Stockfish/pulls/925","html_url":"https://github.com/official-stockfish/Stockfish/pull/925","diff_url":"https://github.com/official-stockfish/Stockfish/pull/925.diff","patch_url":"https://github.com/official-stockfish/Stockfish/pull/925.patch"},"body":"Implement a threefold repetition detection. Below are the examples of problems fixed by this change.\r\n\r\n1. Loosing move in a drawn position.\r\nposition fen 8/k7/3p4/p2P1p2/P2P1P2/8/8/K7 w - - 0 1 moves a1a2 a7a8 a2a1\r\nThe old code suggested a loosing move \"bestmove a8a7\", the new code suggests \"bestmove a8b7\" leading to a draw.\r\n\r\n2. Incorrect evaluation (happened in a real game in TCEC Season 9).\r\nposition fen 4rbkr/1q3pp1/b3pn2/7p/1pN5/1P1BBP1P/P1R2QP1/3R2K1 w - - 5 31 moves e3d4 h8h6 d4e3\r\nThe old code evaluated it as \"cp 0\", the new code evaluation is around \"cp -50\" which is adequate.\r\n\r\nBrings 0.5-1 ELO gain. Passes [-3.00,1.00].\r\n\r\nSTC: http://tests.stockfishchess.org/tests/view/584ece040ebc5903140c5aea\r\nLLR: 2.96 (-2.94,2.94) [-3.00,1.00]\r\nTotal: 47744 W: 8537 L: 8461 D: 30746\r\n\r\nLTC: http://tests.stockfishchess.org/tests/view/584f134d0ebc5903140c5b37\r\nLLR: 2.96 (-2.94,2.94) [-3.00,1.00]\r\nTotal: 36775 W: 4739 L: 4639 D: 27397"},"comment":{"url":"https://api.github.com/repos/official-stockfish/Stockfish/issues/comments/268244112","html_url":"https://github.com/official-stockfish/Stockfish/pull/925#issuecomment-268244112","issue_url":"https://api.github.com/repos/official-stockfish/Stockfish/issues/925","id":268244112,"user":{"login":"mcostalba","id":1099265,"avatar_url":"https://avatars.githubusercontent.com/u/1099265?v=3","gravatar_id":"","url":"https://api.github.com/users/mcostalba","html_url":"https://github.com/mcostalba","followers_url":"https://api.github.com/users/mcostalba/followers","following_url":"https://api.github.com/users/mcostalba/following{/other_user}","gists_url":"https://api.github.com/users/mcostalba/gists{/gist_id}","starred_url":"https://api.github.com/users/mcostalba/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/mcostalba/subscriptions","organizations_url":"https://api.github.com/users/mcostalba/orgs","repos_url":"https://api.github.com/users/mcostalba/repos","events_url":"https://api.github.com/users/mcostalba/events{/privacy}","received_events_url":"https://api.github.com/users/mcostalba/received_events","type":"User","site_admin":false},"created_at":"2016-12-20T13:34:08Z","updated_at":"2016-12-20T13:34:08Z","body":"Also previous code, of course.\n\nOn Tuesday, December 20, 2016, Aram Tumanian <notifications@github.com>\nwrote:\n\n> Because drawDepth is reset at null moves as well as at pawn moves and\n> captures.\n>\n> —\n> You are receiving this because you were mentioned.\n> Reply to this email directly, view it on GitHub\n> <https://github.com/official-stockfish/Stockfish/pull/925#issuecomment-268229629>,\n> or mute the thread\n> <https://github.com/notifications/unsubscribe-auth/ABDGAY3TXEXbJ_Ck46a9HJGp8YdGkbfHks5rJ8fCgaJpZM4LMEQh>\n> .\n>\n"}}
{"actor":{"display_login":"mcostalba"}}