3 <title>Polyglot book format</title>
6 <h1>Polyglot book format</h1>
7 The following description of the Polyglot book format is obtained
8 by inspecting the freely available source code of Polyglot.
9 <h2>A note on copyright</h2> I believe that the algorithm described
10 below may be freely implemented by all GUIs, adapters and engines,
11 including closed source ones. Polyglot itself is GPL but the GPL only
12 covers actual code and not algorithms.
14 The array of 781 random numbers is of course taken from the Polyglot
15 source code but I am pretty sure that a table of random numbers
16 cannot be covered by copyright.
18 Look below for some sample code which is released
21 At the end of this document we discuss an extension of the Polyglot
22 opening book format for Chess960. This extension is implemented in
23 upcoming versions of xboard/winboard.
25 A Polyglot book is a series of "entries" of 16 bytes
34 All integers are stored highest byte first (regardless of size)
36 The entries are ordered according to key. Lowest key first.
39 "key" is a 64 bit hash of a board position. Its computation
42 The starting point is given by the following declaration
47 # define U64(u) (u##ui64)
49 # define U64(u) (u##ULL)
52 const uint64 Random64[781] = {
53 U64(0x9D39247E33776D41), U64(0x2AF7398005AAA5C7), U64(0x44DB015024623547), U64(0x9C15F73E62A76AE2),
54 U64(0x75834465489C0C89), U64(0x3290AC3A203001BF), U64(0x0FBBAD1F61042279), U64(0xE83A908FF2FB60CA),
55 U64(0x0D7E765D58755C10), U64(0x1A083822CEAFE02D), U64(0x9605D5F0E25EC3B0), U64(0xD021FF5CD13A2ED5),
56 U64(0x40BDF15D4A672E32), U64(0x011355146FD56395), U64(0x5DB4832046F3D9E5), U64(0x239F8B2D7FF719CC),
57 U64(0x05D1A1AE85B49AA1), U64(0x679F848F6E8FC971), U64(0x7449BBFF801FED0B), U64(0x7D11CDB1C3B7ADF0),
58 U64(0x82C7709E781EB7CC), U64(0xF3218F1C9510786C), U64(0x331478F3AF51BBE6), U64(0x4BB38DE5E7219443),
59 U64(0xAA649C6EBCFD50FC), U64(0x8DBD98A352AFD40B), U64(0x87D2074B81D79217), U64(0x19F3C751D3E92AE1),
60 U64(0xB4AB30F062B19ABF), U64(0x7B0500AC42047AC4), U64(0xC9452CA81A09D85D), U64(0x24AA6C514DA27500),
61 U64(0x4C9F34427501B447), U64(0x14A68FD73C910841), U64(0xA71B9B83461CBD93), U64(0x03488B95B0F1850F),
62 U64(0x637B2B34FF93C040), U64(0x09D1BC9A3DD90A94), U64(0x3575668334A1DD3B), U64(0x735E2B97A4C45A23),
63 U64(0x18727070F1BD400B), U64(0x1FCBACD259BF02E7), U64(0xD310A7C2CE9B6555), U64(0xBF983FE0FE5D8244),
64 U64(0x9F74D14F7454A824), U64(0x51EBDC4AB9BA3035), U64(0x5C82C505DB9AB0FA), U64(0xFCF7FE8A3430B241),
65 U64(0x3253A729B9BA3DDE), U64(0x8C74C368081B3075), U64(0xB9BC6C87167C33E7), U64(0x7EF48F2B83024E20),
66 U64(0x11D505D4C351BD7F), U64(0x6568FCA92C76A243), U64(0x4DE0B0F40F32A7B8), U64(0x96D693460CC37E5D),
67 U64(0x42E240CB63689F2F), U64(0x6D2BDCDAE2919661), U64(0x42880B0236E4D951), U64(0x5F0F4A5898171BB6),
68 U64(0x39F890F579F92F88), U64(0x93C5B5F47356388B), U64(0x63DC359D8D231B78), U64(0xEC16CA8AEA98AD76),
69 U64(0x5355F900C2A82DC7), U64(0x07FB9F855A997142), U64(0x5093417AA8A7ED5E), U64(0x7BCBC38DA25A7F3C),
70 U64(0x19FC8A768CF4B6D4), U64(0x637A7780DECFC0D9), U64(0x8249A47AEE0E41F7), U64(0x79AD695501E7D1E8),
71 U64(0x14ACBAF4777D5776), U64(0xF145B6BECCDEA195), U64(0xDABF2AC8201752FC), U64(0x24C3C94DF9C8D3F6),
72 U64(0xBB6E2924F03912EA), U64(0x0CE26C0B95C980D9), U64(0xA49CD132BFBF7CC4), U64(0xE99D662AF4243939),
73 U64(0x27E6AD7891165C3F), U64(0x8535F040B9744FF1), U64(0x54B3F4FA5F40D873), U64(0x72B12C32127FED2B),
74 U64(0xEE954D3C7B411F47), U64(0x9A85AC909A24EAA1), U64(0x70AC4CD9F04F21F5), U64(0xF9B89D3E99A075C2),
75 U64(0x87B3E2B2B5C907B1), U64(0xA366E5B8C54F48B8), U64(0xAE4A9346CC3F7CF2), U64(0x1920C04D47267BBD),
76 U64(0x87BF02C6B49E2AE9), U64(0x092237AC237F3859), U64(0xFF07F64EF8ED14D0), U64(0x8DE8DCA9F03CC54E),
77 U64(0x9C1633264DB49C89), U64(0xB3F22C3D0B0B38ED), U64(0x390E5FB44D01144B), U64(0x5BFEA5B4712768E9),
78 U64(0x1E1032911FA78984), U64(0x9A74ACB964E78CB3), U64(0x4F80F7A035DAFB04), U64(0x6304D09A0B3738C4),
79 U64(0x2171E64683023A08), U64(0x5B9B63EB9CEFF80C), U64(0x506AACF489889342), U64(0x1881AFC9A3A701D6),
80 U64(0x6503080440750644), U64(0xDFD395339CDBF4A7), U64(0xEF927DBCF00C20F2), U64(0x7B32F7D1E03680EC),
81 U64(0xB9FD7620E7316243), U64(0x05A7E8A57DB91B77), U64(0xB5889C6E15630A75), U64(0x4A750A09CE9573F7),
82 U64(0xCF464CEC899A2F8A), U64(0xF538639CE705B824), U64(0x3C79A0FF5580EF7F), U64(0xEDE6C87F8477609D),
83 U64(0x799E81F05BC93F31), U64(0x86536B8CF3428A8C), U64(0x97D7374C60087B73), U64(0xA246637CFF328532),
84 U64(0x043FCAE60CC0EBA0), U64(0x920E449535DD359E), U64(0x70EB093B15B290CC), U64(0x73A1921916591CBD),
85 U64(0x56436C9FE1A1AA8D), U64(0xEFAC4B70633B8F81), U64(0xBB215798D45DF7AF), U64(0x45F20042F24F1768),
86 U64(0x930F80F4E8EB7462), U64(0xFF6712FFCFD75EA1), U64(0xAE623FD67468AA70), U64(0xDD2C5BC84BC8D8FC),
87 U64(0x7EED120D54CF2DD9), U64(0x22FE545401165F1C), U64(0xC91800E98FB99929), U64(0x808BD68E6AC10365),
88 U64(0xDEC468145B7605F6), U64(0x1BEDE3A3AEF53302), U64(0x43539603D6C55602), U64(0xAA969B5C691CCB7A),
89 U64(0xA87832D392EFEE56), U64(0x65942C7B3C7E11AE), U64(0xDED2D633CAD004F6), U64(0x21F08570F420E565),
90 U64(0xB415938D7DA94E3C), U64(0x91B859E59ECB6350), U64(0x10CFF333E0ED804A), U64(0x28AED140BE0BB7DD),
91 U64(0xC5CC1D89724FA456), U64(0x5648F680F11A2741), U64(0x2D255069F0B7DAB3), U64(0x9BC5A38EF729ABD4),
92 U64(0xEF2F054308F6A2BC), U64(0xAF2042F5CC5C2858), U64(0x480412BAB7F5BE2A), U64(0xAEF3AF4A563DFE43),
93 U64(0x19AFE59AE451497F), U64(0x52593803DFF1E840), U64(0xF4F076E65F2CE6F0), U64(0x11379625747D5AF3),
94 U64(0xBCE5D2248682C115), U64(0x9DA4243DE836994F), U64(0x066F70B33FE09017), U64(0x4DC4DE189B671A1C),
95 U64(0x51039AB7712457C3), U64(0xC07A3F80C31FB4B4), U64(0xB46EE9C5E64A6E7C), U64(0xB3819A42ABE61C87),
96 U64(0x21A007933A522A20), U64(0x2DF16F761598AA4F), U64(0x763C4A1371B368FD), U64(0xF793C46702E086A0),
97 U64(0xD7288E012AEB8D31), U64(0xDE336A2A4BC1C44B), U64(0x0BF692B38D079F23), U64(0x2C604A7A177326B3),
98 U64(0x4850E73E03EB6064), U64(0xCFC447F1E53C8E1B), U64(0xB05CA3F564268D99), U64(0x9AE182C8BC9474E8),
99 U64(0xA4FC4BD4FC5558CA), U64(0xE755178D58FC4E76), U64(0x69B97DB1A4C03DFE), U64(0xF9B5B7C4ACC67C96),
100 U64(0xFC6A82D64B8655FB), U64(0x9C684CB6C4D24417), U64(0x8EC97D2917456ED0), U64(0x6703DF9D2924E97E),
101 U64(0xC547F57E42A7444E), U64(0x78E37644E7CAD29E), U64(0xFE9A44E9362F05FA), U64(0x08BD35CC38336615),
102 U64(0x9315E5EB3A129ACE), U64(0x94061B871E04DF75), U64(0xDF1D9F9D784BA010), U64(0x3BBA57B68871B59D),
103 U64(0xD2B7ADEEDED1F73F), U64(0xF7A255D83BC373F8), U64(0xD7F4F2448C0CEB81), U64(0xD95BE88CD210FFA7),
104 U64(0x336F52F8FF4728E7), U64(0xA74049DAC312AC71), U64(0xA2F61BB6E437FDB5), U64(0x4F2A5CB07F6A35B3),
105 U64(0x87D380BDA5BF7859), U64(0x16B9F7E06C453A21), U64(0x7BA2484C8A0FD54E), U64(0xF3A678CAD9A2E38C),
106 U64(0x39B0BF7DDE437BA2), U64(0xFCAF55C1BF8A4424), U64(0x18FCF680573FA594), U64(0x4C0563B89F495AC3),
107 U64(0x40E087931A00930D), U64(0x8CFFA9412EB642C1), U64(0x68CA39053261169F), U64(0x7A1EE967D27579E2),
108 U64(0x9D1D60E5076F5B6F), U64(0x3810E399B6F65BA2), U64(0x32095B6D4AB5F9B1), U64(0x35CAB62109DD038A),
109 U64(0xA90B24499FCFAFB1), U64(0x77A225A07CC2C6BD), U64(0x513E5E634C70E331), U64(0x4361C0CA3F692F12),
110 U64(0xD941ACA44B20A45B), U64(0x528F7C8602C5807B), U64(0x52AB92BEB9613989), U64(0x9D1DFA2EFC557F73),
111 U64(0x722FF175F572C348), U64(0x1D1260A51107FE97), U64(0x7A249A57EC0C9BA2), U64(0x04208FE9E8F7F2D6),
112 U64(0x5A110C6058B920A0), U64(0x0CD9A497658A5698), U64(0x56FD23C8F9715A4C), U64(0x284C847B9D887AAE),
113 U64(0x04FEABFBBDB619CB), U64(0x742E1E651C60BA83), U64(0x9A9632E65904AD3C), U64(0x881B82A13B51B9E2),
114 U64(0x506E6744CD974924), U64(0xB0183DB56FFC6A79), U64(0x0ED9B915C66ED37E), U64(0x5E11E86D5873D484),
115 U64(0xF678647E3519AC6E), U64(0x1B85D488D0F20CC5), U64(0xDAB9FE6525D89021), U64(0x0D151D86ADB73615),
116 U64(0xA865A54EDCC0F019), U64(0x93C42566AEF98FFB), U64(0x99E7AFEABE000731), U64(0x48CBFF086DDF285A),
117 U64(0x7F9B6AF1EBF78BAF), U64(0x58627E1A149BBA21), U64(0x2CD16E2ABD791E33), U64(0xD363EFF5F0977996),
118 U64(0x0CE2A38C344A6EED), U64(0x1A804AADB9CFA741), U64(0x907F30421D78C5DE), U64(0x501F65EDB3034D07),
119 U64(0x37624AE5A48FA6E9), U64(0x957BAF61700CFF4E), U64(0x3A6C27934E31188A), U64(0xD49503536ABCA345),
120 U64(0x088E049589C432E0), U64(0xF943AEE7FEBF21B8), U64(0x6C3B8E3E336139D3), U64(0x364F6FFA464EE52E),
121 U64(0xD60F6DCEDC314222), U64(0x56963B0DCA418FC0), U64(0x16F50EDF91E513AF), U64(0xEF1955914B609F93),
122 U64(0x565601C0364E3228), U64(0xECB53939887E8175), U64(0xBAC7A9A18531294B), U64(0xB344C470397BBA52),
123 U64(0x65D34954DAF3CEBD), U64(0xB4B81B3FA97511E2), U64(0xB422061193D6F6A7), U64(0x071582401C38434D),
124 U64(0x7A13F18BBEDC4FF5), U64(0xBC4097B116C524D2), U64(0x59B97885E2F2EA28), U64(0x99170A5DC3115544),
125 U64(0x6F423357E7C6A9F9), U64(0x325928EE6E6F8794), U64(0xD0E4366228B03343), U64(0x565C31F7DE89EA27),
126 U64(0x30F5611484119414), U64(0xD873DB391292ED4F), U64(0x7BD94E1D8E17DEBC), U64(0xC7D9F16864A76E94),
127 U64(0x947AE053EE56E63C), U64(0xC8C93882F9475F5F), U64(0x3A9BF55BA91F81CA), U64(0xD9A11FBB3D9808E4),
128 U64(0x0FD22063EDC29FCA), U64(0xB3F256D8ACA0B0B9), U64(0xB03031A8B4516E84), U64(0x35DD37D5871448AF),
129 U64(0xE9F6082B05542E4E), U64(0xEBFAFA33D7254B59), U64(0x9255ABB50D532280), U64(0xB9AB4CE57F2D34F3),
130 U64(0x693501D628297551), U64(0xC62C58F97DD949BF), U64(0xCD454F8F19C5126A), U64(0xBBE83F4ECC2BDECB),
131 U64(0xDC842B7E2819E230), U64(0xBA89142E007503B8), U64(0xA3BC941D0A5061CB), U64(0xE9F6760E32CD8021),
132 U64(0x09C7E552BC76492F), U64(0x852F54934DA55CC9), U64(0x8107FCCF064FCF56), U64(0x098954D51FFF6580),
133 U64(0x23B70EDB1955C4BF), U64(0xC330DE426430F69D), U64(0x4715ED43E8A45C0A), U64(0xA8D7E4DAB780A08D),
134 U64(0x0572B974F03CE0BB), U64(0xB57D2E985E1419C7), U64(0xE8D9ECBE2CF3D73F), U64(0x2FE4B17170E59750),
135 U64(0x11317BA87905E790), U64(0x7FBF21EC8A1F45EC), U64(0x1725CABFCB045B00), U64(0x964E915CD5E2B207),
136 U64(0x3E2B8BCBF016D66D), U64(0xBE7444E39328A0AC), U64(0xF85B2B4FBCDE44B7), U64(0x49353FEA39BA63B1),
137 U64(0x1DD01AAFCD53486A), U64(0x1FCA8A92FD719F85), U64(0xFC7C95D827357AFA), U64(0x18A6A990C8B35EBD),
138 U64(0xCCCB7005C6B9C28D), U64(0x3BDBB92C43B17F26), U64(0xAA70B5B4F89695A2), U64(0xE94C39A54A98307F),
139 U64(0xB7A0B174CFF6F36E), U64(0xD4DBA84729AF48AD), U64(0x2E18BC1AD9704A68), U64(0x2DE0966DAF2F8B1C),
140 U64(0xB9C11D5B1E43A07E), U64(0x64972D68DEE33360), U64(0x94628D38D0C20584), U64(0xDBC0D2B6AB90A559),
141 U64(0xD2733C4335C6A72F), U64(0x7E75D99D94A70F4D), U64(0x6CED1983376FA72B), U64(0x97FCAACBF030BC24),
142 U64(0x7B77497B32503B12), U64(0x8547EDDFB81CCB94), U64(0x79999CDFF70902CB), U64(0xCFFE1939438E9B24),
143 U64(0x829626E3892D95D7), U64(0x92FAE24291F2B3F1), U64(0x63E22C147B9C3403), U64(0xC678B6D860284A1C),
144 U64(0x5873888850659AE7), U64(0x0981DCD296A8736D), U64(0x9F65789A6509A440), U64(0x9FF38FED72E9052F),
145 U64(0xE479EE5B9930578C), U64(0xE7F28ECD2D49EECD), U64(0x56C074A581EA17FE), U64(0x5544F7D774B14AEF),
146 U64(0x7B3F0195FC6F290F), U64(0x12153635B2C0CF57), U64(0x7F5126DBBA5E0CA7), U64(0x7A76956C3EAFB413),
147 U64(0x3D5774A11D31AB39), U64(0x8A1B083821F40CB4), U64(0x7B4A38E32537DF62), U64(0x950113646D1D6E03),
148 U64(0x4DA8979A0041E8A9), U64(0x3BC36E078F7515D7), U64(0x5D0A12F27AD310D1), U64(0x7F9D1A2E1EBE1327),
149 U64(0xDA3A361B1C5157B1), U64(0xDCDD7D20903D0C25), U64(0x36833336D068F707), U64(0xCE68341F79893389),
150 U64(0xAB9090168DD05F34), U64(0x43954B3252DC25E5), U64(0xB438C2B67F98E5E9), U64(0x10DCD78E3851A492),
151 U64(0xDBC27AB5447822BF), U64(0x9B3CDB65F82CA382), U64(0xB67B7896167B4C84), U64(0xBFCED1B0048EAC50),
152 U64(0xA9119B60369FFEBD), U64(0x1FFF7AC80904BF45), U64(0xAC12FB171817EEE7), U64(0xAF08DA9177DDA93D),
153 U64(0x1B0CAB936E65C744), U64(0xB559EB1D04E5E932), U64(0xC37B45B3F8D6F2BA), U64(0xC3A9DC228CAAC9E9),
154 U64(0xF3B8B6675A6507FF), U64(0x9FC477DE4ED681DA), U64(0x67378D8ECCEF96CB), U64(0x6DD856D94D259236),
155 U64(0xA319CE15B0B4DB31), U64(0x073973751F12DD5E), U64(0x8A8E849EB32781A5), U64(0xE1925C71285279F5),
156 U64(0x74C04BF1790C0EFE), U64(0x4DDA48153C94938A), U64(0x9D266D6A1CC0542C), U64(0x7440FB816508C4FE),
157 U64(0x13328503DF48229F), U64(0xD6BF7BAEE43CAC40), U64(0x4838D65F6EF6748F), U64(0x1E152328F3318DEA),
158 U64(0x8F8419A348F296BF), U64(0x72C8834A5957B511), U64(0xD7A023A73260B45C), U64(0x94EBC8ABCFB56DAE),
159 U64(0x9FC10D0F989993E0), U64(0xDE68A2355B93CAE6), U64(0xA44CFE79AE538BBE), U64(0x9D1D84FCCE371425),
160 U64(0x51D2B1AB2DDFB636), U64(0x2FD7E4B9E72CD38C), U64(0x65CA5B96B7552210), U64(0xDD69A0D8AB3B546D),
161 U64(0x604D51B25FBF70E2), U64(0x73AA8A564FB7AC9E), U64(0x1A8C1E992B941148), U64(0xAAC40A2703D9BEA0),
162 U64(0x764DBEAE7FA4F3A6), U64(0x1E99B96E70A9BE8B), U64(0x2C5E9DEB57EF4743), U64(0x3A938FEE32D29981),
163 U64(0x26E6DB8FFDF5ADFE), U64(0x469356C504EC9F9D), U64(0xC8763C5B08D1908C), U64(0x3F6C6AF859D80055),
164 U64(0x7F7CC39420A3A545), U64(0x9BFB227EBDF4C5CE), U64(0x89039D79D6FC5C5C), U64(0x8FE88B57305E2AB6),
165 U64(0xA09E8C8C35AB96DE), U64(0xFA7E393983325753), U64(0xD6B6D0ECC617C699), U64(0xDFEA21EA9E7557E3),
166 U64(0xB67C1FA481680AF8), U64(0xCA1E3785A9E724E5), U64(0x1CFC8BED0D681639), U64(0xD18D8549D140CAEA),
167 U64(0x4ED0FE7E9DC91335), U64(0xE4DBF0634473F5D2), U64(0x1761F93A44D5AEFE), U64(0x53898E4C3910DA55),
168 U64(0x734DE8181F6EC39A), U64(0x2680B122BAA28D97), U64(0x298AF231C85BAFAB), U64(0x7983EED3740847D5),
169 U64(0x66C1A2A1A60CD889), U64(0x9E17E49642A3E4C1), U64(0xEDB454E7BADC0805), U64(0x50B704CAB602C329),
170 U64(0x4CC317FB9CDDD023), U64(0x66B4835D9EAFEA22), U64(0x219B97E26FFC81BD), U64(0x261E4E4C0A333A9D),
171 U64(0x1FE2CCA76517DB90), U64(0xD7504DFA8816EDBB), U64(0xB9571FA04DC089C8), U64(0x1DDC0325259B27DE),
172 U64(0xCF3F4688801EB9AA), U64(0xF4F5D05C10CAB243), U64(0x38B6525C21A42B0E), U64(0x36F60E2BA4FA6800),
173 U64(0xEB3593803173E0CE), U64(0x9C4CD6257C5A3603), U64(0xAF0C317D32ADAA8A), U64(0x258E5A80C7204C4B),
174 U64(0x8B889D624D44885D), U64(0xF4D14597E660F855), U64(0xD4347F66EC8941C3), U64(0xE699ED85B0DFB40D),
175 U64(0x2472F6207C2D0484), U64(0xC2A1E7B5B459AEB5), U64(0xAB4F6451CC1D45EC), U64(0x63767572AE3D6174),
176 U64(0xA59E0BD101731A28), U64(0x116D0016CB948F09), U64(0x2CF9C8CA052F6E9F), U64(0x0B090A7560A968E3),
177 U64(0xABEEDDB2DDE06FF1), U64(0x58EFC10B06A2068D), U64(0xC6E57A78FBD986E0), U64(0x2EAB8CA63CE802D7),
178 U64(0x14A195640116F336), U64(0x7C0828DD624EC390), U64(0xD74BBE77E6116AC7), U64(0x804456AF10F5FB53),
179 U64(0xEBE9EA2ADF4321C7), U64(0x03219A39EE587A30), U64(0x49787FEF17AF9924), U64(0xA1E9300CD8520548),
180 U64(0x5B45E522E4B1B4EF), U64(0xB49C3B3995091A36), U64(0xD4490AD526F14431), U64(0x12A8F216AF9418C2),
181 U64(0x001F837CC7350524), U64(0x1877B51E57A764D5), U64(0xA2853B80F17F58EE), U64(0x993E1DE72D36D310),
182 U64(0xB3598080CE64A656), U64(0x252F59CF0D9F04BB), U64(0xD23C8E176D113600), U64(0x1BDA0492E7E4586E),
183 U64(0x21E0BD5026C619BF), U64(0x3B097ADAF088F94E), U64(0x8D14DEDB30BE846E), U64(0xF95CFFA23AF5F6F4),
184 U64(0x3871700761B3F743), U64(0xCA672B91E9E4FA16), U64(0x64C8E531BFF53B55), U64(0x241260ED4AD1E87D),
185 U64(0x106C09B972D2E822), U64(0x7FBA195410E5CA30), U64(0x7884D9BC6CB569D8), U64(0x0647DFEDCD894A29),
186 U64(0x63573FF03E224774), U64(0x4FC8E9560F91B123), U64(0x1DB956E450275779), U64(0xB8D91274B9E9D4FB),
187 U64(0xA2EBEE47E2FBFCE1), U64(0xD9F1F30CCD97FB09), U64(0xEFED53D75FD64E6B), U64(0x2E6D02C36017F67F),
188 U64(0xA9AA4D20DB084E9B), U64(0xB64BE8D8B25396C1), U64(0x70CB6AF7C2D5BCF0), U64(0x98F076A4F7A2322E),
189 U64(0xBF84470805E69B5F), U64(0x94C3251F06F90CF3), U64(0x3E003E616A6591E9), U64(0xB925A6CD0421AFF3),
190 U64(0x61BDD1307C66E300), U64(0xBF8D5108E27E0D48), U64(0x240AB57A8B888B20), U64(0xFC87614BAF287E07),
191 U64(0xEF02CDD06FFDB432), U64(0xA1082C0466DF6C0A), U64(0x8215E577001332C8), U64(0xD39BB9C3A48DB6CF),
192 U64(0x2738259634305C14), U64(0x61CF4F94C97DF93D), U64(0x1B6BACA2AE4E125B), U64(0x758F450C88572E0B),
193 U64(0x959F587D507A8359), U64(0xB063E962E045F54D), U64(0x60E8ED72C0DFF5D1), U64(0x7B64978555326F9F),
194 U64(0xFD080D236DA814BA), U64(0x8C90FD9B083F4558), U64(0x106F72FE81E2C590), U64(0x7976033A39F7D952),
195 U64(0xA4EC0132764CA04B), U64(0x733EA705FAE4FA77), U64(0xB4D8F77BC3E56167), U64(0x9E21F4F903B33FD9),
196 U64(0x9D765E419FB69F6D), U64(0xD30C088BA61EA5EF), U64(0x5D94337FBFAF7F5B), U64(0x1A4E4822EB4D7A59),
197 U64(0x6FFE73E81B637FB3), U64(0xDDF957BC36D8B9CA), U64(0x64D0E29EEA8838B3), U64(0x08DD9BDFD96B9F63),
198 U64(0x087E79E5A57D1D13), U64(0xE328E230E3E2B3FB), U64(0x1C2559E30F0946BE), U64(0x720BF5F26F4D2EAA),
199 U64(0xB0774D261CC609DB), U64(0x443F64EC5A371195), U64(0x4112CF68649A260E), U64(0xD813F2FAB7F5C5CA),
200 U64(0x660D3257380841EE), U64(0x59AC2C7873F910A3), U64(0xE846963877671A17), U64(0x93B633ABFA3469F8),
201 U64(0xC0C0F5A60EF4CDCF), U64(0xCAF21ECD4377B28C), U64(0x57277707199B8175), U64(0x506C11B9D90E8B1D),
202 U64(0xD83CC2687A19255F), U64(0x4A29C6465A314CD1), U64(0xED2DF21216235097), U64(0xB5635C95FF7296E2),
203 U64(0x22AF003AB672E811), U64(0x52E762596BF68235), U64(0x9AEBA33AC6ECC6B0), U64(0x944F6DE09134DFB6),
204 U64(0x6C47BEC883A7DE39), U64(0x6AD047C430A12104), U64(0xA5B1CFDBA0AB4067), U64(0x7C45D833AFF07862),
205 U64(0x5092EF950A16DA0B), U64(0x9338E69C052B8E7B), U64(0x455A4B4CFE30E3F5), U64(0x6B02E63195AD0CF8),
206 U64(0x6B17B224BAD6BF27), U64(0xD1E0CCD25BB9C169), U64(0xDE0C89A556B9AE70), U64(0x50065E535A213CF6),
207 U64(0x9C1169FA2777B874), U64(0x78EDEFD694AF1EED), U64(0x6DC93D9526A50E68), U64(0xEE97F453F06791ED),
208 U64(0x32AB0EDB696703D3), U64(0x3A6853C7E70757A7), U64(0x31865CED6120F37D), U64(0x67FEF95D92607890),
209 U64(0x1F2B1D1F15F6DC9C), U64(0xB69E38A8965C6B65), U64(0xAA9119FF184CCCF4), U64(0xF43C732873F24C13),
210 U64(0xFB4A3D794A9A80D2), U64(0x3550C2321FD6109C), U64(0x371F77E76BB8417E), U64(0x6BFA9AAE5EC05779),
211 U64(0xCD04F3FF001A4778), U64(0xE3273522064480CA), U64(0x9F91508BFFCFC14A), U64(0x049A7F41061A9E60),
212 U64(0xFCB6BE43A9F2FE9B), U64(0x08DE8A1C7797DA9B), U64(0x8F9887E6078735A1), U64(0xB5B4071DBFC73A66),
213 U64(0x230E343DFBA08D33), U64(0x43ED7F5A0FAE657D), U64(0x3A88A0FBBCB05C63), U64(0x21874B8B4D2DBC4F),
214 U64(0x1BDEA12E35F6A8C9), U64(0x53C065C6C8E63528), U64(0xE34A1D250E7A8D6B), U64(0xD6B04D3B7651DD7E),
215 U64(0x5E90277E7CB39E2D), U64(0x2C046F22062DC67D), U64(0xB10BB459132D0A26), U64(0x3FA9DDFB67E2F199),
216 U64(0x0E09B88E1914F7AF), U64(0x10E8B35AF3EEAB37), U64(0x9EEDECA8E272B933), U64(0xD4C718BC4AE8AE5F),
217 U64(0x81536D601170FC20), U64(0x91B534F885818A06), U64(0xEC8177F83F900978), U64(0x190E714FADA5156E),
218 U64(0xB592BF39B0364963), U64(0x89C350C893AE7DC1), U64(0xAC042E70F8B383F2), U64(0xB49B52E587A1EE60),
219 U64(0xFB152FE3FF26DA89), U64(0x3E666E6F69AE2C15), U64(0x3B544EBE544C19F9), U64(0xE805A1E290CF2456),
220 U64(0x24B33C9D7ED25117), U64(0xE74733427B72F0C1), U64(0x0A804D18B7097475), U64(0x57E3306D881EDB4F),
221 U64(0x4AE7D6A36EB5DBCB), U64(0x2D8D5432157064C8), U64(0xD1E649DE1E7F268B), U64(0x8A328A1CEDFE552C),
222 U64(0x07A3AEC79624C7DA), U64(0x84547DDC3E203C94), U64(0x990A98FD5071D263), U64(0x1A4FF12616EEFC89),
223 U64(0xF6F7FD1431714200), U64(0x30C05B1BA332F41C), U64(0x8D2636B81555A786), U64(0x46C9FEB55D120902),
224 U64(0xCCEC0A73B49C9921), U64(0x4E9D2827355FC492), U64(0x19EBB029435DCB0F), U64(0x4659D2B743848A2C),
225 U64(0x963EF2C96B33BE31), U64(0x74F85198B05A2E7D), U64(0x5A0F544DD2B1FB18), U64(0x03727073C2E134B1),
226 U64(0xC7F6AA2DE59AEA61), U64(0x352787BAA0D7C22F), U64(0x9853EAB63B5E0B35), U64(0xABBDCDD7ED5C0860),
227 U64(0xCF05DAF5AC8D77B0), U64(0x49CAD48CEBF4A71E), U64(0x7A4C10EC2158C4A6), U64(0xD9E92AA246BF719E),
228 U64(0x13AE978D09FE5557), U64(0x730499AF921549FF), U64(0x4E4B705B92903BA4), U64(0xFF577222C14F0A3A),
229 U64(0x55B6344CF97AAFAE), U64(0xB862225B055B6960), U64(0xCAC09AFBDDD2CDB4), U64(0xDAF8E9829FE96B5F),
230 U64(0xB5FDFC5D3132C498), U64(0x310CB380DB6F7503), U64(0xE87FBB46217A360E), U64(0x2102AE466EBB1148),
231 U64(0xF8549E1A3AA5E00D), U64(0x07A69AFDCC42261A), U64(0xC4C118BFE78FEAAE), U64(0xF9F4892ED96BD438),
232 U64(0x1AF3DBE25D8F45DA), U64(0xF5B4B0B0D2DEEEB4), U64(0x962ACEEFA82E1C84), U64(0x046E3ECAAF453CE9),
233 U64(0xF05D129681949A4C), U64(0x964781CE734B3C84), U64(0x9C2ED44081CE5FBD), U64(0x522E23F3925E319E),
234 U64(0x177E00F9FC32F791), U64(0x2BC60A63A6F3B3F2), U64(0x222BBFAE61725606), U64(0x486289DDCC3D6780),
235 U64(0x7DC7785B8EFDFC80), U64(0x8AF38731C02BA980), U64(0x1FAB64EA29A2DDF7), U64(0xE4D9429322CD065A),
236 U64(0x9DA058C67844F20C), U64(0x24C0E332B70019B0), U64(0x233003B5A6CFE6AD), U64(0xD586BD01C5C217F6),
237 U64(0x5E5637885F29BC2B), U64(0x7EBA726D8C94094B), U64(0x0A56A5F0BFE39272), U64(0xD79476A84EE20D06),
238 U64(0x9E4C1269BAA4BF37), U64(0x17EFEE45B0DEE640), U64(0x1D95B0A5FCF90BC6), U64(0x93CBE0B699C2585D),
239 U64(0x65FA4F227A2B6D79), U64(0xD5F9E858292504D5), U64(0xC2B5A03F71471A6F), U64(0x59300222B4561E00),
240 U64(0xCE2F8642CA0712DC), U64(0x7CA9723FBB2E8988), U64(0x2785338347F2BA08), U64(0xC61BB3A141E50E8C),
241 U64(0x150F361DAB9DEC26), U64(0x9F6A419D382595F4), U64(0x64A53DC924FE7AC9), U64(0x142DE49FFF7A7C3D),
242 U64(0x0C335248857FA9E7), U64(0x0A9C32D5EAE45305), U64(0xE6C42178C4BBB92E), U64(0x71F1CE2490D20B07),
243 U64(0xF1BCC3D275AFE51A), U64(0xE728E8C83C334074), U64(0x96FBF83A12884624), U64(0x81A1549FD6573DA5),
244 U64(0x5FA7867CAF35E149), U64(0x56986E2EF3ED091B), U64(0x917F1DD5F8886C61), U64(0xD20D8C88C8FFE65F),
245 U64(0x31D71DCE64B2C310), U64(0xF165B587DF898190), U64(0xA57E6339DD2CF3A0), U64(0x1EF6E6DBB1961EC9),
246 U64(0x70CC73D90BC26E24), U64(0xE21A6B35DF0C3AD7), U64(0x003A93D8B2806962), U64(0x1C99DED33CB890A1),
247 U64(0xCF3145DE0ADD4289), U64(0xD0E4427A5514FB72), U64(0x77C621CC9FB3A483), U64(0x67A34DAC4356550B),
248 U64(0xF8D626AAAF278509),
251 The array Random64 is in fact a concatenation of four subarrays
253 RandomPiece (offset: 0, length: 768)
254 RandomCastle (offset: 768, length: 4)
255 RandomEnPassant (offset: 772, length: 8)
256 RandomTurn (offset: 780, length: 1)
258 "key" is a so-called "Zobrist hash function". In other words it is
259 the <b>exclusive or</b> of entries taken from each of the
260 subarrays described above.
264 key=piece^castle^enpassant^turn;
268 "piece" is the exclusive or of entries from
269 RandomPiece, one for each piece on the board. The offset of the entry
270 in RandomPiece corresponding to a piece is computed as follows.
272 offset_piece=64*kind_of_piece+8*row+file;
274 "row" and "file" are counted from 0 to 7. With this convention one has
277 ======================
284 "kind_of_piece" is encoded as follows
301 "castle" is the exclusive or of entries from
302 RandomCastle. The offsets are computed as follows.
304 white can castle short 0
305 white can castle long 1
306 black can castle short 2
307 black can castle long 3
309 If none of these flags apply then castle=0.
311 Note that these flags represent "potential future castling" as in the
312 FEN standard even if such castling is currently not possible due to blocking
313 pieces or enemy attacks.
315 In other words these flags are all true in the starting position and are
316 only updated after the appropriate king, rook or castling moves.
320 <h3>enpassent</h3> If the opponent has performed a double pawn push
321 and there is now a pawn next to it belonging to the player to move then
322 "enpassant" is the entry from RandomEnPassant whose offset is the file
323 of the pushed pawn (counted from 0(=a) to 7(=h)). If this does not
324 apply then enpassant=0.
326 Note that this is <b>different from the FEN standard</b>. In the FEN standard
327 the presence of an "en passant target square" after a double pawn push
329 <p> Also note that it is irrelevant if the potential en passant
330 capturing move is legal or not (examples where it would not be legal are
331 when the capturing pawn is pinned or when the double pawn push was a
336 If white is to move then "turn" is the sole entry of RandomTurn.
337 If not then "turn" is zero.
340 Here are some test keys. They were computed using Toga II
341 and checked using the algorithm described above.
345 FEN=rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1
349 FEN=rnbqkbnr/pppppppp/8/8/4P3/8/PPPP1PPP/RNBQKBNR b KQkq e3 0 1
352 position after e2e4 d75
353 FEN=rnbqkbnr/ppp1pppp/8/3p4/4P3/8/PPPP1PPP/RNBQKBNR w KQkq d6 0 2
356 position after e2e4 d7d5 e4e5
357 FEN=rnbqkbnr/ppp1pppp/8/3pP3/8/8/PPPP1PPP/RNBQKBNR b KQkq - 0 2
360 position after e2e4 d7d5 e4e5 f7f5
361 FEN=rnbqkbnr/ppp1p1pp/8/3pPp2/8/8/PPPP1PPP/RNBQKBNR w KQkq f6 0 3
364 position after e2e4 d7d5 e4e5 f7f5 e1e2
365 FEN=rnbqkbnr/ppp1p1pp/8/3pPp2/8/8/PPPPKPPP/RNBQ1BNR b kq - 0 3
368 position after e2e4 d7d5 e4e5 f7f5 e1e2 e8f7
369 FEN=rnbq1bnr/ppp1pkpp/8/3pPp2/8/8/PPPPKPPP/RNBQ1BNR w - - 0 4
372 position after a2a4 b7b5 h2h4 b5b4 c2c4
373 FEN=rnbqkbnr/p1pppppp/8/8/PpP4P/8/1P1PPPP1/RNBQKBNR b KQkq c3 0 3
376 position after a2a4 b7b5 h2h4 b5b4 c2c4 b4c3 a1a3
377 FEN=rnbqkbnr/p1pppppp/8/8/P6P/R1p5/1P1PPPP1/1NBQKBNR b Kkq - 0 4
383 "move" is a bit field with the following meaning (bit 0 is the least
387 ===================================
392 12,13,14 promotion piece
394 "promotion piece" is encoded as follows
402 If the move is "0" (a1a1) then it should simply be ignored. It seems to me that
403 in that case one might as well delete the entry from the book.
405 <h3>Castling moves</h3> Castling moves are represented somewhat
406 unconventially as follows (this convention is related to Chess960, see
414 It is technically possible that these moves are legal non-castling
415 moves. So before deciding that these are really castling moves the
416 implementation may for example verify that there is really a king
419 In the Polyglot source code this field is called "count" but it is in fact
420 a measure for the quality of the move. <b>It should be at least one.</b>
422 The Polyglot book generator sets it to 2*(wins)+(draws), globally
423 scaled to fit into 16 bits. A move with a weight of zero is deleted
424 from the book. This is just a convention and book authors
425 are free to set this field according to their taste (as long as it is at least one).
427 If random play is enabled in Polyglot then the probability that
428 a move is selected is its weight divided by the sum of the weights
429 of all the moves in the given position.
430 <h3>A note on zero weights</h3>
431 Polyglot assumes that weights are at least one since a zero
432 weight means the move should not be played, and hence you might as
433 well delete the entry from the book (which the Polyglot book generator does).
435 Nonetheless, if you really insist, an entry with zero weight can be
436 approximated by giving it very low probability. This is what Scid does.
438 <h2>learn</h2> "learn" is set to zero by the Polyglot book generator.
439 If you set "BookLearn=true" in polyglot.ini then this field
440 is used to record learning information. However I do not know of any
441 program that uses this information. Also this means the Polyglot should
442 have write access to the opening book which on Unix systems will probably
443 not be the case if the book has been installed centrally.
446 The following sample code is released in the public domain.
449 <a href=pg_key.c>pg_key.c</a>: This little utility computes the PG key
450 of a FEN. Note that it does ZERO error checking on the legality
451 of the FEN and hence will segfault if something is wrong.
454 <a href=pg_show.c>pg_show.c</a>: This utility looks up a PG key in a PG book
455 and prints out the moves and their (relative) weights.
459 Here are a few utilities: <a href=pg_utils-0.2.tar.gz>pg_utils-0.2.tar.gz</a>. They are released under the FreeBSD license.
460 <H2>Extension to Chess960</H2>
461 We assume that the reader is familar
462 with the rules of Chess960 (also called Fisher Random Chess or
464 <a href=http://en.wikipedia.org/wiki/Fischer_Random_Chess>http://en.wikipedia.org/wiki/Fischer_Random_Chess</a>.
466 The Zobrist hash function used in Polyglot does not keep track of
467 which rook has castling rights if there are multiple rooks present on
468 the same side of the king. However it is rather unlikely that this
469 situation would occur in the opening. So the ambiguity can be resolved
470 in a satisfactory way by making the following convention.
472 <b> Positions in which a rook has castling rights which is not an outer
473 rook (closest to a or h file) should not be included in the book. </b>
475 Nonetheless this is an unsatisfactory situation. Therefore the
476 upcoming versions of xboard/winboard extend the Polyglot hash function
477 in such a way that it takes into account the full castling rights in
479 <b>removing the need of the above disambiguating convention</b>. This is done in a backward compatible way. I.e. ordinary
480 chess positions or Chess960 positions in which there is no castling
481 ambiguity will keep their old hash key.
483 The above declaration of RandomCastle is replaced by
485 const uint64 RandomCastle[16]={
486 < to be filled in >
489 In this case "castle" will be the exclusive or of entries taken from
490 RandomCastle, one for each rook that has castling rights (so at most
493 The offset for a rook that has castling rights is computed as follows.
495 <li> If the rook is an outer rook (i.e. closest to the a or h file) then
498 0 if the rook is white and on the king side
499 1 if the rook is white and on the queen side
500 2 if the rook is black and on the king side
501 3 if the rook is black and on the queen side
503 (this is like in ordinary chess)
505 <li> If the rook is not an outer rook then the offset is
507 3+file if the rook is white
508 9+file if the rook is black
510 where "file" denotes the file the rook is on, encoded in the usual way, i.e.
511 b=1,c=2,d=3,e=4,f=5,g=6.
514 <h3>Encoding of moves</h3> A castling move is encoded as a usual move
515 (see above) in which the "from square" is the position of the king and
516 the "to square" is the position of the rook. This is to maintain
517 compatibility with various Fruit derivatives.