below are two random locally minimal 25*25-sudokus. They have a unique solution but removing any clue results in a puzzle with multiple solutions. It took my computer many hours to create these ! Should you find some other minimal 25*25-sudokus somewhere, I'd like to know about it. ------------------------------------------------------------------------ (1) +-----+-----+-----+-----+-----+ |...E5|.4..F|D..B.|.KMG.|...1.| |7....|O..2.|..G.L|1.C64|..B3.| |1P...|.....|I...K|...O.|.DN2.| |DK.M.|...J.|1H...|L..I2|9G.EO| |H.L..|.G.B6|8.7F.|95...|....4| +-----+-----+-----+-----+-----+ |6FH.9|5....|.4...|.G...|.81..| |...8.|..2..|N...1|6.LM5|.4..9| |P4I..|..D6B|JK98.|...CN|M...2| |NO3..|4F1I.|PB...|.E.8.|J....| |...B7|NE.C.|LGFH6|..J2.|.OK.A| +-----+-----+-----+-----+-----+ |..932|.MO7.|.1...|B..4F|.....| |...D4|.....|..K..|.C3..|.A9PM| |.6...|.AE.4|5...D|..K..|H.C..| |M.7KO|..F..|2PH.A|....6|...B.| |.H..P|L....|.I3.9|GM.N.|O.F4.| +-----+-----+-----+-----+-----+ |..K..|7..4.|E..D.|P.NA.|.B89G| |F....|.P.AI|.92..|OD4.J|3K657| |.2...|..L.M|F.P..|.91.H|A...J| |O...A|3.KN.|...5J|E....|....H| |.3.JM|F18.D|..AKH|.6.B.|E.I.L| +-----+-----+-----+-----+-----+ |..E..|2...5|...G.|...P.|K1L..| |...C.|..GE.|.F.J.|H.5..|.....| |..M.K|J6I8.|AO.L.|C.BF.|.5...| |B5...|.7..9|..8.P|2L...|.FO.I| |...P.|....O|47I..|J....|2C...| +-----+-----+-----+-----+-----+ and the same in short-notation: ...E5.4..FD..B..KMG....1. 7....O..2...G.L1.C64..B3. 1P........I...K...O..DN2. DK.M....J.1H...L..I29G.EO H.L...G.B68.7F.95.......4 6FH.95.....4....G....81.. ...8...2..N...16.LM5.4..9 P4I....D6BJK98....CNM...2 NO3..4F1I.PB....E.8.J.... ...B7NE.C.LGFH6..J2..OK.A ..932.MO7..1...B..4F..... ...D4.......K...C3...A9PM .6....AE.45...D..K..H.C.. M.7KO..F..2PH.A....6...B. .H..PL.....I3.9GM.N.O.F4. ..K..7..4.E..D.P.NA..B89G F.....P.AI.92..OD4.J3K657 .2.....L.MF.P...91.HA...J O...A3.KN....5JE........H .3.JMF18.D..AKH.6.B.E.I.L ..E..2...5...G....P.K1L.. ...C...GE..F.J.H.5....... ..M.KJ6I8.AO.L.C.BF..5... B5....7..9..8.P2L....FO.I ...P.....O47I..J....2C... and the same in more computer-readable format: 0, 0, 0,14, 5, 0, 4, 0, 0,15,13, 0, 0,11, 0, 0,20,22,16, 0, 0, 0, 0, 1, 0 7, 0, 0, 0, 0,24, 0, 0, 2, 0, 0, 0,16, 0,21, 1, 0,12, 6, 4, 0, 0,11, 3, 0 1,25, 0, 0, 0, 0, 0, 0, 0, 0,18, 0, 0, 0,20, 0, 0, 0,24, 0, 0,13,23, 2, 0 13,20, 0,22, 0, 0, 0, 0,19, 0, 1,17, 0, 0, 0,21, 0, 0,18, 2, 9,16, 0,14,24 17, 0,21, 0, 0, 0,16, 0,11, 6, 8, 0, 7,15, 0, 9, 5, 0, 0, 0, 0, 0, 0, 0, 4 6,15,17, 0, 9, 5, 0, 0, 0, 0, 0, 4, 0, 0, 0, 0,16, 0, 0, 0, 0, 8, 1, 0, 0 0, 0, 0, 8, 0, 0, 0, 2, 0, 0,23, 0, 0, 0, 1, 6, 0,21,22, 5, 0, 4, 0, 0, 9 25, 4,18, 0, 0, 0, 0,13, 6,11,19,20, 9, 8, 0, 0, 0, 0,12,23,22, 0, 0, 0, 2 23,24, 3, 0, 0, 4,15, 1,18, 0,25,11, 0, 0, 0, 0,14, 0, 8, 0,19, 0, 0, 0, 0 0, 0, 0,11, 7,23,14, 0,12, 0,21,16,15,17, 6, 0, 0,19, 2, 0, 0,24,20, 0,10 0, 0, 9, 3, 2, 0,22,24, 7, 0, 0, 1, 0, 0, 0,11, 0, 0, 4,15, 0, 0, 0, 0, 0 0, 0, 0,13, 4, 0, 0, 0, 0, 0, 0, 0,20, 0, 0, 0,12, 3, 0, 0, 0,10, 9,25,22 0, 6, 0, 0, 0, 0,10,14, 0, 4, 5, 0, 0, 0,13, 0, 0,20, 0, 0,17, 0,12, 0, 0 22, 0, 7,20,24, 0, 0,15, 0, 0, 2,25,17, 0,10, 0, 0, 0, 0, 6, 0, 0, 0,11, 0 0,17, 0, 0,25,21, 0, 0, 0, 0, 0,18, 3, 0, 9,16,22, 0,23, 0,24, 0,15, 4, 0 0, 0,20, 0, 0, 7, 0, 0, 4, 0,14, 0, 0,13, 0,25, 0,23,10, 0, 0,11, 8, 9,16 15, 0, 0, 0, 0, 0,25, 0,10,18, 0, 9, 2, 0, 0,24,13, 4, 0,19, 3,20, 6, 5, 7 0, 2, 0, 0, 0, 0, 0,21, 0,22,15, 0,25, 0, 0, 0, 9, 1, 0,17,10, 0, 0, 0,19 24, 0, 0, 0,10, 3, 0,20,23, 0, 0, 0, 0, 5,19,14, 0, 0, 0, 0, 0, 0, 0, 0,17 0, 3, 0,19,22,15, 1, 8, 0,13, 0, 0,10,20,17, 0, 6, 0,11, 0,14, 0,18, 0,21 0, 0,14, 0, 0, 2, 0, 0, 0, 5, 0, 0, 0,16, 0, 0, 0, 0,25, 0,20, 1,21, 0, 0 0, 0, 0,12, 0, 0, 0,16,14, 0, 0,15, 0,19, 0,17, 0, 5, 0, 0, 0, 0, 0, 0, 0 0, 0,22, 0,20,19, 6,18, 8, 0,10,24, 0,21, 0,12, 0,11,15, 0, 0, 5, 0, 0, 0 11, 5, 0, 0, 0, 0, 7, 0, 0, 9, 0, 0, 8, 0,25, 2,21, 0, 0, 0, 0,15,24, 0,18 0, 0, 0,25, 0, 0, 0, 0, 0,24, 4, 7,18, 0, 0,19, 0, 0, 0, 0, 2,12, 0, 0, 0 ----------------------------------------------------------------------------- (2) +-----+-----+-----+-----+-----+ |.1.KA|..B.D|P42N.|...7G|..E6.| |...8.|..NIO|...6G|..5HF|.C..A| |.6...|3....|...J.|4K..B|H.P.D| |CO4D.|.9AKE|...I.|.J126|35...| |.B57.|H68..|.9.OK|.C..N|4.2F.| +-----+-----+-----+-----+-----+ |.I.1.|.....|..J..|7.C8D|A3...| |...32|..7M.|.E...|....4|FB.91| |6..4.|...2.|3.P1.|AO...|..5.7| |...F.|E.I84|6B97O|.5...|.PLH.| |8.B..|AN...|..L..|..G9.|.M6K.| +-----+-----+-----+-----+-----+ |BM.L3|.C.5.|....E|..O.K|67...| |...2.|1.K..|9..5.|.....|G..A.| |.A...|.H...|..4.L|16IN.|..D3.| |.K...|..4..|BD.P.|G....|ENF..| |GE75.|....P|K3..C|J...A|..M2L| +-----+-----+-----+-----+-----+ |...94|CJ.B.|..7.F|M..P8|I...E| |5..OI|PK...|.1E.6|94N..|M.B..| |D.A.6|..2..|..N..|..EO.|C4K.F| |.CP.7|.46..|I58..|H...J|.1A.O| |.2...|9.GE7|.C.AP|I....|.D...| +-----+-----+-----+-----+-----+ |1..I.|.B5H.|O.K2.|.....|.EN..| |....P|O....|C6.GI|.N3..|8....| |....5|.A..G|8...1|K.PB.|J...H| |...MK|8I.N.|A...4|.7J61|...5G| |2....|...16|D....|LMH..|7A3OK| +-----+-----+-----+-----+-----+ 0, 1, 0,20,10, 0, 0,11, 0,13,25, 4, 2,23, 0, 0, 0, 0, 7,16, 0, 0,14, 6, 0 0, 0, 0, 8, 0, 0, 0,23,18,24, 0, 0, 0, 6,16, 0, 0, 5,17,15, 0,12, 0, 0,10 0, 6, 0, 0, 0, 3, 0, 0, 0, 0, 0, 0, 0,19, 0, 4,20, 0, 0,11,17, 0,25, 0,13 12,24, 4,13, 0, 0, 9,10,20,14, 0, 0, 0,18, 0, 0,19, 1, 2, 6, 3, 5, 0, 0, 0 0,11, 5, 7, 0,17, 6, 8, 0, 0, 0, 9, 0,24,20, 0,12, 0, 0,23, 4, 0, 2,15, 0 0,18, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0,19, 0, 0, 7, 0,12, 8,13,10, 3, 0, 0, 0 0, 0, 0, 3, 2, 0, 0, 7,22, 0, 0,14, 0, 0, 0, 0, 0, 0, 0, 4,15,11, 0, 9, 1 6, 0, 0, 4, 0, 0, 0, 0, 2, 0, 3, 0,25, 1, 0,10,24, 0, 0, 0, 0, 0, 5, 0, 7 0, 0, 0,15, 0,14, 0,18, 8, 4, 6,11, 9, 7,24, 0, 5, 0, 0, 0, 0,25,21,17, 0 8, 0,11, 0, 0,10,23, 0, 0, 0, 0, 0,21, 0, 0, 0, 0,16, 9, 0, 0,22, 6,20, 0 11,22, 0,21, 3, 0,12, 0, 5, 0, 0, 0, 0, 0,14, 0, 0,24, 0,20, 6, 7, 0, 0, 0 0, 0, 0, 2, 0, 1, 0,20, 0, 0, 9, 0, 0, 5, 0, 0, 0, 0, 0, 0,16, 0, 0,10, 0 0,10, 0, 0, 0, 0,17, 0, 0, 0, 0, 0, 4, 0,21, 1, 6,18,23, 0, 0, 0,13, 3, 0 0,20, 0, 0, 0, 0, 0, 4, 0, 0,11,13, 0,25, 0,16, 0, 0, 0, 0,14,23,15, 0, 0 16,14, 7, 5, 0, 0, 0, 0, 0,25,20, 3, 0, 0,12,19, 0, 0, 0,10, 0, 0,22, 2,21 0, 0, 0, 9, 4,12,19, 0,11, 0, 0, 0, 7, 0,15,22, 0, 0,25, 8,18, 0, 0, 0,14 5, 0, 0,24,18,25,20, 0, 0, 0, 0, 1,14, 0, 6, 9, 4,23, 0, 0,22, 0,11, 0, 0 13, 0,10, 0, 6, 0, 0, 2, 0, 0, 0, 0,23, 0, 0, 0, 0,14,24, 0,12, 4,20, 0,15 0,12,25, 0, 7, 0, 4, 6, 0, 0,18, 5, 8, 0, 0,17, 0, 0, 0,19, 0, 1,10, 0,24 0, 2, 0, 0, 0, 9, 0,16,14, 7, 0,12, 0,10,25,18, 0, 0, 0, 0, 0,13, 0, 0, 0 1, 0, 0,18, 0, 0,11, 5,17, 0,24, 0,20, 2, 0, 0, 0, 0, 0, 0, 0,14,23, 0, 0 0, 0, 0, 0,25,24, 0, 0, 0, 0,12, 6, 0,16,18, 0,23, 3, 0, 0, 8, 0, 0, 0, 0 0, 0, 0, 0, 5, 0,10, 0, 0,16, 8, 0, 0, 0, 1,20, 0,25,11, 0,19, 0, 0, 0,17 0, 0, 0,22,20, 8,18, 0,23, 0,10, 0, 0, 0, 4, 0, 7,19, 6, 1, 0, 0, 0, 5,16 2, 0, 0, 0, 0, 0, 0, 0, 1, 6,13, 0, 0, 0, 0,21,22,17, 0, 0, 7,10, 3,24,20 created by sterten@aol.com Nov.17,2005