O.T. Bláthy - Cyril Banderier
Checkmate in 290 moves., 1929

 This problem is the longest checkmate problem, due to the great componist Ottó Bláthy. The position is not legal (easy retroanalysis), and it is easy to convert it to a legal position, but I give the original Bláthy position. Bláthy won a prize for this position, in 1929. The analysis/solution given here was done by Cyril Banderier, in 1992 (and is online since 1998). Don't deduce from this date it took me more than 63 years to solve this problem ;-) 1.Rd1+ Bd4 2.c4+ Kd6 3.Rxg1 Bc3 4.Rd1+ Bd4 OK the Zugzwang is in place, now white has to find how to use it. The idea is to play Kb6 WHEN black's bishop is in a8, then black can only plays its pawns (b2,h7,h6,h2) and white hopes to capture them and at the end hopes also to capture Bb7 and to mate ?!? Let's go on and see: 5.Ka5 Bb7 6.Ka4 Ba8 7.Ka3 Bb7 8.Ka2 Ba8 9.Kb1 Bb7 10.Kc2 Ba8 11.Kd3 Bb7 The funny thing is that is not possible to leave the e3 pawn, because of a quick mate (e2 chekmates in e5, with the rook sticking the bishop in d4.) 12.Re1 Now comes the great trick : White has to lost one time in order to get Kb6 when black's bishop is in a8. 12...Ba8 13.Rf1! Bb7 14.Rd1 Ba8 15.Kc2 Bb7 16.Kb1 Ba8 17.Ka2 Bb7 18.Ka3 Ba8 19.Ka4 Bb7 20.Ka5 Ba8 21.Kb6 h4 You got it, simply repeat this Zugzwang sequence until black has no more moves. 22.Ka5 Bb7 23.Ka4 Ba8 24.Ka3 Bb7 25.Ka2 Ba8 26.Kb1 Bb7 27.Kc2 Ba8 28.Kd3 Bb7 29.Rf1 Ba8 30.Re1 Bb7 31.Rd1 Ba8 32.Kc2 Bb7 33.Kb1 Ba8 34.Ka2 Bb7 35.Ka3 Ba8 36.Ka4 Bb7 37.Ka5 Ba8 38.Kb6 h3 39.Ka5 Bb7 40.Ka4 Ba8 41.Ka3 Bb7 42.Ka2 Ba8 43.Kb1 Bb7 44.Kc2 Ba8 45.Kd3 Bb7 46.Rf1 Ba8 47.Re1 Bb7 If during the game, black plays Be5, dont take the bishop, go on the Zugzwang. The scheme Kb6 and pawn checkmating with b4xc5+ is usefull in some positions. 48.Rd1 Ba8 49.Kc2 Bb7 50.Kb1 Ba8 51.Ka2 Bb7 52.Ka3 Ba8 53.Ka4 Bb7 54.Ka5 Ba8 55.Kb6 h2 56.Ka5 Bb7 57.Ka4 Ba8 58.Ka3 Bb7 59.Ka2 Ba8 60.Kb1 Bb7 61.Kc2 Ba8 62.Kd3 Bb7 63.Rf1 Ba8 64.Re1 Bb7 65.Rd1 Ba8 66.Kc2 Bb7 67.Kb1 Ba8 68.Ka2 Bb7 69.Ka3 Ba8 70.Ka4 Bb7 71.Ka5 Ba8 72.Kb6 h5 73.Ka5 Bb7 74.Ka4 Ba8 75.Ka3 Bb7 76.Ka2 Ba8 77.Kb1 Bb7 78.Kc2 Ba8 79.Kd3 Bb7 80.Rf1 Ba8 81.Re1 Bb7 82.Rd1 Ba8 83.Kc2 Bb7 84.Kb1 Ba8 85.Ka2 Bb7 86.Ka3 Ba8 87.Ka4 Bb7 88.Ka5 Ba8 89.Kb6 h4 90.Ka5 Bb7 91.Ka4 Ba8 92.Ka3 Bb7 93.Ka2 Ba8 94.Kb1 Bb7 95.Kc2 Ba8 96.Kd3 Bb7 97.Rf1 Ba8 98.Re1 Bb7 99.Rd1 Ba8 100.Kc2 Bb7 101.Kb1 Ba8 102.Ka2 Bb7 103.Ka3 Ba8 104.Ka4 Bb7 105.Ka5 Ba8 106.Kb6 h3 107.Ka5 Bb7 108.Ka4 Ba8 109.Ka3 Bb7 110.Ka2 Ba8 111.Kb1 Bb7 112.Kc2 Ba8 113.Kd3 Bb7 114.Rf1 Ba8 115.Re1 Bb7 116.Rd1 Ba8 117.Kc2 Bb7 118.Kb1 Ba8 119.Ka2 Bb7 120.Ka3 Ba8 121.Ka4 Bb7 122.Ka5 Ba8 123.Kb6 h6 124.Ka5 Bb7 125.Ka4 Ba8 126.Ka3 Bb7 127.Ka2 Ba8 128.Kb1 Bb7 129.Kc2 Ba8 130.Kd3 Bb7 131.Rf1 Ba8 132.Re1 Bb7 133.Rd1 Ba8 134.Kc2 Bb7 135.Kb1 Ba8 136.Ka2 Bb7 137.Ka3 Ba8 138.Ka4 Bb7 139.Ka5 Ba8 140.Kb6 h5 141.Ka5 Bb7 142.Ka4 Ba8 143.Ka3 Bb7 144.Ka2 Ba8 145.Kb1 Bb7 146.Kc2 Ba8 147.Kd3 Bb7 148.Rf1 Ba8 149.Re1 Bb7 150.Rd1 Ba8 151.Kc2 Bb7 152.Kb1 Ba8 153.Ka2 Bb7 154.Ka3 Ba8 155.Ka4 Bb7 156.Ka5 Ba8 157.Kb6 h4 158.Ka5 Bb7 159.Ka4 Ba8 160.Ka3 Bb7 161.Ka2 Ba8 162.Kb1 Bb7 163.Kc2 Ba8 164.Kd3 Bb7 165.Rf1 Ba8 166.Re1 Bb7 167.Rd1 Ba8 168.Kc2 Bb7 169.Kb1 Ba8 170.Ka2 Bb7 171.Ka3 Ba8 172.Ka4 Bb7 173.Ka5 Ba8 174.Kb6 h1=Q 175.Rxh1 Bg7 176.Rd1+ Bd4 177.Ka5 Bb7 178.Ka4 Ba8 179.Ka3 Bb7 180.Ka2 Ba8 181.Kb1 Bb7 182.Kc2 Ba8 183.Kd3 Bb7 184.Rf1 Ba8 185.Re1 Bb7 186.Rd1 Ba8 187.Kc2 Bb7 188.Kb1 Ba8 189.Ka2 Bb7 190.Ka3 Ba8 191.Ka4 Bb7 192.Ka5 Ba8 193.Kb6 h2 194.Ka5 Bb7 195.Ka4 Ba8 196.Ka3 Bb7 197.Ka2 Ba8 198.Kb1 Bb7 199.Kc2 Ba8 200.Kd3 Bb7 201.Rf1 Ba8 202.Re1 Bb7 203.Rd1 Ba8 204.Kc2 Bb7 205.Kb1 Ba8 206.Ka2 Bb7 207.Ka3 Ba8 208.Ka4 Bb7 209.Ka5 Ba8 210.Kb6 h3 211.Ka5 Bb7 212.Ka4 Ba8 213.Ka3 Bb7 214.Ka2 Ba8 215.Kb1 Bb7 216.Kc2 Ba8 217.Kd3 Bb7 218.Rf1 Ba8 219.Re1 Bb7 220.Rd1 Ba8 221.Kc2 Bb7 222.Kb1 Ba8 223.Ka2 Bb7 224.Ka3 Ba8 225.Ka4 Bb7 226.Ka5 Ba8 227.Kb6 h1=Q 228.Rxh1 Bg7 229.Rd1+ Bd4 230.Ka5 Bb7 231.Ka4 Ba8 232.Ka3 Bb7 233.Ka2 Ba8 234.Kb1 Bb7 235.Kc2 Ba8 236.Kd3 Bb7 237.Rf1 Ba8 238.Re1 Bb7 239.Rd1 Ba8 240.Kc2 Bb7 241.Kb1 Ba8 242.Ka2 Bb7 243.Ka3 Ba8 244.Ka4 Bb7 245.Ka5 Ba8 246.Kb6 h2 247.Ka5 Bb7 248.Ka4 Ba8 249.Ka3 Bb7 250.Ka2 Ba8 251.Kb1 Bb7 252.Kc2 Ba8 253.Kd3 Bb7 254.Rf1 Ba8 255.Re1 Bb7 256.Rd1 Ba8 257.Kc2 Bb7 258.Kb1 Ba8 259.Ka2 Bb7 260.Ka3 Ba8 261.Ka4 Bb7 262.Ka5 Ba8 263.Kb6 h1=Q 264.Rxh1 Bg7 265.Rd1+ Bd4 266.Ka5 Bb7 267.Ka4 Ba8 268.Ka3 Bb7 269.Ka2 Ba8 270.Kb1 Bb7 271.Kc2 Ba8 272.Kd3 Bb7 273.Rf1 Ba8 274.Re1 Bb7 275.Rd1 Ba8 276.Kc2 Bb7 277.Kb1 Ba8 278.Ka2 Bb7 279.Ka3 Ba8 280.Ka4 Bb7 281.Ka5 Ba8 282.Kb6 Bb7 284.Rxb1 Be5 285.Rd1+ Bd4 286.Rxd4+ cxd4 287.Kb6 d3 288.a8=Q Rxb8+ 289.Qxb8 dxe2 290.Qxd8# If you are aware of any longer mate problem or if you find any reference to Bláthy's problem in the literature, tell it ! I'm only aware of an article by François Le Lionnais about Chess in the french "Encyclopedia Universalis" which gives the initial position, but not its solution. Note that with endgame databases / brute-force analysis of computers, it was shown that the deepest checkmate with 5 pieces is a 262 moves mate with K+N+N vs K+R, a 267 moves mate with 6 pieces, and, in 2006, Marc Bourzutschky and Yakov Konoval found a position potentially leading to a 526 moves mate Tim Krabbé's comment on this KQN/KRBN [youtube version]. This figure has to be confirmed, as databases are not complete, and the distance to mate for this position is only upper bounds via a capture and then a reduction to a smaller size problem. ( Lutz Neweklowsky created a 530 moves mate problem based on this position). A 202 moves mate position was actually reached in game in 1976. A legal 270 moves mate position was created by Nenad Petrović in 1969. [local copy, youtube version ] There is another checkmate problem in 292 moves by Bláthy, I will comment on it later because the solutions I saw online are buggy. If you have any information improving/completing all those figures, please email me. I also suggest to have a look on R. Stanley's slides for a talk on extremal chess problems. Another nice (short) famous checkmate problem : the Saavedra position. Questions/comments on this page: Cyril.Banderier at lipn.univ-paris13.fr 1-0

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