An absolutely brilliant study!

[acase]

Sadly, I think this may be somewhat cooked. Nd5 is indeed a beautiful move and winning, but letting Crystal do some deep analysis further in, it seems like the engine's top choice Re4 is likely also winning. Getting scores of ~ +4.5 anyway.

You're right.
Even if the line given in HHdbVI
8/2p2p1p/3k1p2/pn6/PNp4p/r3Rp1P/2P2P2/BK6 w - - 0 1
1.Re4 Rxa4 2.Na6 Na3+ 3.Kc1 Nxc2 4.Bxf6 Nb4 5.Nxb4 axb4 6.Rxc4 c5
is suboptimal at least as for 5.Nxb4? (5.Rd4+! get's the winning eval of >4 of your Crystal's, you wrote about) but also for 4...Nb4?, 4...Na1 5.Be5+ was 2x1-0 with SF dev- Crystal- Crystal- SF dev at 45'+15", 15 threads of 16x3.5GHz and 16G hash each, 6men Syzygys:

[pgn][Event "AMD, Schnellschach 45.0min+15.0sek"]
[Site "Dort"]
[Date "2023.03.23"]
[Round "1"]
[White "Stockfish"]
[Black "Crystal 5 KWK"]
[Result "1-0"]
[Annotator "1.23;1.02"]
[SetUp "1"]
[FEN "8/2p2p1p/3k1p2/pn6/PNp4p/r3Rp1P/2P2P2/BK6 w - - 0 1"]
[PlyCount "199"]
[TimeControl "2700+15"]

{AMD Ryzen 9 5950X 16-Core Processor 3400 MHz W=50.9 plies; 17.780kN/s; 1.197.553.199 TBAs B=37.7 plies; 16.798kN/s; 1.049.727.312 TBAs 0.86;1.04: 'AMD Ryzen 9 5950X 16-Core Processor 3400 MHz W=38.5 plies; 18.854kN/s; 998.624.273 TBAs B=64.0 plies; 22.671kN/s; 1.457.527.477 TBAs '} 1. Re4 Rxa4 2. Na6 Na3+ 3. Kc1 Nxc2 4. Bxf6 Na1 5. Be5+ {Beide letzter Buchzug} Kd5 {1.02/44 172} (5... Kc6 {1.04/54 416} 6. Rf4 {0.86/44 174} Nb3+ {1.03/56 0} 7. Kb2 {0.80/46 171} Kb6 {1.03/58 0} 8. Rf6+ {0.95/47 112} c6 {1.04/61 0} 9. Nc7 {0.91/48 145} Ra1 {1.14/59 44} 10. Nd5+ {0.73/49 194} Kc5 {1.35/53 8} 11. Nc3 {0.72/47 56} Rf1 {1.58/57 130} 12. Bd6+ {0.67/47 42} Kb6 {1.51/59 17} 13. Rxf3 {0.52/45 47} Nc5 {1.64/59 132} 14. Bxc5+ {0.75/48 0} Kxc5 {1.64/60 178} 15. Rf5+ {0.66/50 114} Kd4 {1.77/62 89} 16. Kc2 {0.40/46 55} Rh1 {1.87/78 75} 17. Rf4+ {0.46/47 33} Kc5 {1.98/68 107} 18. Rxh4 {0.50/47 10} Rh2 {1.98/75 43} 19. Nd1 {0.53/49 287} a4 {2.08/68 0} 20. Rh5+ {0.29/48 91} Kb4 {2.24/78 84} 21. Rxh7 {0.53/49 17} a3 {2.24/73 38} 22. Rh8 {0.84/45 32} f5 {2.49/65 200} 23. h4 {0.98/49 27} f4 {2.49/64 30 (Th3)} 24. h5 {0.99/48 255} Rh3 {2.54/66 9} 25. h6 {0.96/50 241} a2 {2.67/69 0} 26. Rb8+ {1.03/42 40} Kc5 {2.67/65 15} 27. Ra8 {0.86/41 29} Rxh6 {2.67/65 37} 28. Rxa2 {1.02/40 8} Rh3 {2.67/62 87} 29. Ra5+ {1.10/44 173} Kd4 {3.08/53 28} 30. Rf5 {1.04/39 4} Ke4 {3.08/59 58} 31. Rc5 {1.00/41 37} Kf3 {3.08/46 30 (Th6)} 32. Rxc6 {2.08/36 70} Rh8 {14.09/45 538 (Th7)} 33. Rxc4 {2.46/36 184} Ra8 {198.30/51 0} 34. Kc1 {2.61/35 163 (Kd2)} Ra1+ {199.02/49 97} 35. Kd2 {2.68/34 7 (Kc2)} Ra7 {198.92/52 30} 36. Rc3+ {2.75/32 19 (Tc5)} Kg2 {199.18/65 28} 37. Kc1 {3.00/33 81 (Kc2)} Ra1+ {199.18/65 39} 38. Kc2 {2.85/31 34} Ra8 {199.24/74 9 (Ta6)} 39. Kb2 {3.50/29 41} Rb8+ {199.26/74 0 (Td8)} 40. Kc1 {3.88/31 74} Ra8 {199.28/70 154 (Te8)} 41. Rc2 {4.87/28 29} Ra1+ {199.30/79 16} 42. Kd2 {5.07/28 22} Kf1 {199.32/80 62 (Ta8)} 43. Rc4 {7.47/28 44} Ra2+ {199.34/81 0} 44. Kc1 {12.58/27 116 (Kd3)} Ra1+ {199.36/81 121} 45. Kc2 {97.44/27 0} Ke2 {199.38/82 34} 46. Re4+ {98.39/28 7} Kf3 {199.40/80 36} 47. Rd4 {98.43/36 32} Ra2+ {199.42/79 194} 48. Kc1 {98.45/41 0} Ra1+ {199.44/81 163 (Ta8)} 49. Kb2 {98.45/38 19} Ra7 {199.46/76 0 (Ta8)} 50. Rd2 {98.51/43 80} Rb7+ {199.48/81 0} 51. Kc2 {98.51/41 28} Rc7+ {199.50/77 0} 52. Nc3 {98.51/41 6} Kg2 {199.52/76 19 (Tc5)} 53. Kb3 {98.51/40 7} Rb7+ {199.54/75 15 (Kf3)} 54. Kc4 {98.51/38 21} Rc7+ {199.56/76 0} 55. Kb4 {98.61/41 38} Rb7+ {199.58/74 0} 56. Nb5 {98.61/39 7} Rb8 {199.62/69 94 (Te7)} 57. Kc4 {98.61/36 7} Rc8+ {199.64/68 31 (Te8)} 58. Kd3 {98.67/39 22} Re8 {199.66/67 0} 59. Ra2 {98.63/37 16 (Sd4)} Re5 {199.66/66 38 (Td8+)} 60. Rb2 {98.67/38 15 (Sd4)} Re8 {199.68/59 19} 61. Nd4 {98.63/38 0} f3 {199.72/55 7} 62. Nf5 {98.67/32 1} Rd8+ {199.74/60 22} 63. Kc4 {98.73/33 9} Kf1 {199.76/59 0} 64. Ng3+ {98.75/31 23 (Se3+)} Kg2 {199.78/58 6} 65. Ne4 {98.79/33 8} Rd7 {199.80/57 28 (Tc8+)} 66. Rb5 {98.79/32 10} Kf1 {199.82/51 0} 67. Rb3 {98.85/35 19} Kg2 {199.86/48 0} 68. Rd3 {98.85/33 10} Rf7 {199.90/50 0 (Te7)} 69. Kd4 {98.85/35 23} Rf8 {199.92/48 39 (Tb7)} 70. Rb3 {98.87/28 13 (Ke3)} Kh3 {199.92/44 7} 71. Ke3 {98.89/34 29} Kh4 {199.94/40 4 (Kg4)} 72. Rb6 {98.95/38 11 (Tb4)} Rf7 {200.00/42 15 (Kg4)} 73. Rf6 {99.69/27 10} Ra7 {200.00/45 24} 74. Kf4 {99.71/31 0} Kh3 {200.00/37 27} 75. Rg6 {99.67/33 24 (Kxf3)} Rf7+ {#33/42 42} 76. Nf6 {99.81/33 0 (Tf6)} Rb7 {#24/51 20 (Ta7)} 77. Nd5 {#24/31 22 (Kxf3)} Rf7+ {#24/44 5} 78. Rf6 {#23/36 19} Rh7 {#21/55 0} 79. Ne3 {#22/37 12 (Kxf3)} Kh4 {#22/53 7} 80. Nf5+ {#21/35 18 (Tg6)} Kh5 {#23/55 11} 81. Ra6 {#20/35 0 (Sg3+)} Rh8 {#19/66 24} 82. Re6 {#19/36 13} Rh7 {#18/33 27} 83. Re7 {#18/35 0} Kg6 {#17/79 11} 84. Rxh7 {#17/36 16} Kxh7 {1/0 0} 85. Kxf3 {2/1 0} Kg6 {2/0 0} 86. Ke4 {1/0 0} Kf6 {1/0 0} 87. f3 {1/1 0} Kg5 {1/0 0} 88. f4+ {2/1 0} Kf6 {2/0 0} 89. Nd4 {1/0 0} Kg6 {1/0 0} 90. f5+ {3/1 0} Kf6 {3/1 0} 91. Kf4 {2/0 0} Ke7 {2/0 0} 92. Ke5 {1/0 0} Kf7 {1/0 0} 93. f6 {2/1 0} Kg6 {2/0 0} 94. Ke6 {1/1 0} Kh6 {1/0 0} 95. f7 {2/1 0} Kg7 {2/1 0} 96. Ke7 {1/0 0} Kh6 {1/0 0} 97. f8=Q+ {4/1 0} Kg5 {4/0 0} 98. Qf3 {3/0 0} Kh4 {3/0 0} 99. Kf7 {2/0 0} Kg5 {2/1 0} 100. Ne6+ {1/1 0 1-0 (100) Crystal 5 KWK-Stockfish Dort 2023 [0.86;1.04]}) 6. Re3 {1.23/41 129} Nb3+ {1.52/42 62} 7. Kb2 {1.27/41 33} h5 {1.63/43 118} 8. Bg7 {1.54/43 0} Kc6 {1.58/44 113} 9. Rxf3 {1.63/41 0} Kb6 {1.83/46 261} 10. Nb8 {1.75/43 8} Rb4 {1.61/45 187} 11. Rxf7 {2.12/42 104 (Tf6+)} Nd4+ {2.53/38 183} 12. Kc1 {2.20/42 0} c3 {2.67/43 474 (Sb5)} 13. Bxd4+ {2.48/44 133} Rxd4 {2.92/41 0} 14. Kc2 {2.61/47 105} Kb5 {3.06/41 0} 15. Kxc3 {2.72/52 69} Rc4+ {3.66/45 390 (Ta4)} 16. Kd3 {3.09/44 72} Rc1 {3.93/41 18} 17. Nd7 {3.17/50 65} Rh1 {4.35/41 3} 18. Rf5+ {3.24/51 134} Kb4 {4.77/41 0} 19. Kd2 {3.80/52 280 (Se5)} Rxh3 {5.15/40 112} 20. Ne5 {4.13/48 0} Kb5 {5.13/39 58} 21. Nd3+ {4.13/50 5} Ka6 {5.17/39 51} 22. Nc5+ {4.13/51 71} Kb6 {5.25/41 0} 23. Na4+ {4.57/44 72} Ka6 {5.15/40 47} 24. Rxh5 {4.57/52 15} Rh1 {5.49/39 77} 25. Nc3 {4.57/42 0} h3 {5.62/32 47} 26. Rh6+ {5.09/44 16} Kb7 {5.66/40 288} 27. Ne4 {5.73/46 0} c6 {5.83/33 35} 28. Rh4 {6.53/46 572} Kb6 {6.17/40 0} 29. Ng5 {7.34/48 149} Rg1 {6.65/35 32 (Th2)} 30. Nxh3 {7.54/36 534} Rh1 {7.07/35 0} 31. Kc3 {8.65/30 97} c5 {6.93/34 246 (Th2)} 32. Rh7 {12.34/34 121} a4 {8.07/33 0} 33. Ng5 {20.66/34 60} Rc1+ {8.74/32 0} 34. Kb2 {79.89/40 32} Rc4 {9.38/33 50} 35. Re7 {79.91/43 17 (Th3)} Rf4 {11.59/35 162} 36. Rf7 {198.15/50 0} Rb4+ {11.61/34 36} 37. Ka3 {198.95/48 40} Kb5 {13.44/28 0} 38. Rf3 {199.09/55 40} Rg4 {11.24/29 0} 39. Ne6 {199.41/54 83 (Sf7)} Rg6 {12.22/25 10} 40. Nc7+ {199.45/56 13 (Te3)} Kc6 {27.11/30 42} 41. Ne8 {199.49/65 0} Rg4 {97.11/26 11} 42. Rf5 {199.53/70 19 (Sf6)} Rd4 {15.06/29 37} 43. Nf6 {199.55/68 0} Kb5 {97.55/29 19} 44. Nd5 {199.57/66 42} Rd3+ {97.57/31 0} 45. Kb2 {199.59/73 32} Kc4 {97.74/32 0} 46. Ne3+ {199.61/72 28} Kb5 {97.88/41 0} 47. Rf4 {199.63/71 171} Kc6 {98.58/39 0 (Td2+)} 48. Kc2 {199.67/66 46} Ra3 {98.58/38 1} 49. Rf6+ {199.69/63 9} Kb7 {98.58/38 23 (Kd7)} 50. Nd1 {199.71/57 8 (Sc4)} Ra2+ {98.64/36 69} 51. Kb1 {199.73/64 0 (Kd3)} Rd2 {14.66/25 5} 52. Nc3 {199.75/62 38 (Sb2)} a3 {98.64/34 6} 53. Ne4 {199.77/53 1} a2+ {98.64/33 8 (Tb2+)} 54. Ka1 {199.83/63 7} Rc2 {98.64/32 1} 55. Rf3 {199.85/50 13} Kb6 {98.64/33 0 (Ka6)} 56. Rc3 {199.87/53 44 (Sc3)} Re2 {98.60/32 16} 57. f3 {199.89/50 0 (Te3)} Kb5 {98.88/40 56} 58. Rxc5+ {199.91/52 0} Kb4 {98.90/40 7} 59. Rc3 {199.93/50 28} Rg2 {98.92/43 0} 60. Rd3 {199.95/45 34 (Te3)} Rh2 {98.94/44 16 (Tc2)} 61. Nd2 {#39/38 3 (Td2)} Rh1+ {98.98/48 11 (Th6)} 62. Kxa2 {#36/44 8} Rh4 {6/1 0 (Th2)} 63. Ne4 {5/0 0} Kc4 {5/0 0} 64. Rb3 {4/1 0} Kd5 {4/0 0} 65. Nc3+ {3/1 0} Kc4 {3/0 0} 66. Ne2 {2/1 0} Rh2 {2/0 0} 67. Rb2 {1/1 0} Rf2 {1/0 0} 68. f4 {8/1 0} Rf1 {8/1 0} 69. Rd2 {7/0 0} Rf2 {7/0 0} 70. Kb2 {6/0 0} Kb4 {6/0 0} 71. Rc2 {5/1 0} Rf3 {5/0 0} 72. Rc7 {4/0 0} Rf2 {4/0 0} 73. Kc2 {3/1 0} Rxe2+ {4/1 0} 74. Kd3 {3/1 0} Rf2 {3/1 0} 75. Ke4 {2/1 0} Re2+ {2/1 0} 76. Kf3 {1/1 0} Re1 {1/0 0} 77. f5 {7/1 0} Rf1+ {7/0 0} 78. Ke4 {6/0 0} Rf2 {6/0 0} 79. Ke5 {5/0 0} Re2+ {5/1 0} 80. Kd4 {4/0 0} Rd2+ {4/1 0} 81. Ke3 {3/1 0} Rd6 {3/1 0} 82. Kf4 {2/1 0} Ra6 {2/0 0} 83. Rf7 {1/1 0} Ra2 {1/0 0} 84. f6 {7/1 0} Kc5 {7/1 0} 85. Rd7 {6/1 0} Rf2+ {6/0 0} 86. Kg5 {5/1 0} Kc6 {5/1 0} 87. Ra7 {4/0 0} Kb6 {4/1 0} 88. Re7 {3/1 0} Rg2+ {3/1 0} 89. Kh4 {2/1 0} Rh2+ {2/1 0} 90. Kg3 {1/1 0} Rh8 {1/0 0} 91. f7 {6/1 0} Rf8 {6/1 0} 92. Kf4 {5/0 0} Kc5 {5/0 0} 93. Ke5 {4/0 0} Rh8 {4/1 0} 94. Re8 {3/0 0} Rh5+ {3/1 0} 95. Kf6 {2/0 0} Rh6+ {2/1 0} 96. Kg5 {1/0 0} Rh5+ {1/0 0} 97. Kxh5 {1/1 0} Kd4 {1/0 0} 98. f8=Q {3/1 0} Kc3 {3/1 0} 99. Re4 {2/0 0} Kd2 {2/0 0} 100. Qc5 {1/0 0} 1-0
[/pgn]

Hi Peter,

I ran a few games and also came to the same conclusion that 1.Rd4! is actually better than the main line because the win is shorter, however I think they would call this a "Dual" (meaning that it has 2 solutions) rather than a "cook", because a cook would mean that the the original solution does not work.

There is a way to "fix" this study but it takes the charm and beauty out of the first move because it makes the 1.Nd5! move forced. The proposed solution(s) would be by putting a black piece on the square d5 like a knight/bishop, or we could move one of the black king side pawns to d5 like the one on h7, also we could move the black pawn on the square f7 to f5 so that the white rook can no longer go to the e4 square, and another way to "fix" it is to start the position with white's second move in the main line.

Here's what the positions would look like:

[pgn][Event "Computer chess game"]
[Site "WORKSTATION-PC"]
[Date "2023.03.24"]
[Round "?"]
[White "Workstation"]
[Black "Stockfish_23022721_x64_bmi2"]
[Result "*"]
[BlackElo "2000"]
[Time "11:22:45"]
[WhiteElo "2000"]
[TimeControl "0+300"]
[SetUp "1"]
[FEN "8/2p2p1p/3k1p2/pn1n4/PNp4p/r3Rp1P/2P2P2/BK6 w - - 0 1"]
[Termination "unterminated"]
[PlyCount "0"]
[WhiteType "human"]
[BlackType "human"]

*[/pgn]




[pgn][Event "Computer chess game"]
[Site "WORKSTATION-PC"]
[Date "2023.03.24"]
[Round "?"]
[White "Workstation"]
[Black "Stockfish_23022721_x64_bmi2"]
[Result "*"]
[BlackElo "2000"]
[Time "11:24:17"]
[WhiteElo "2000"]
[TimeControl "0+300"]
[SetUp "1"]
[FEN "8/2p2p2/3k1p2/pn1p4/PNp4p/r3Rp1P/2P2P2/BK6 w - - 0 1"]
[Termination "unterminated"]
[PlyCount "0"]
[WhiteType "human"]
[BlackType "human"]

*[/pgn]


[pgn][Event "Computer chess game"]
[Site "WORKSTATION-PC"]
[Date "2023.03.24"]
[Round "?"]
[White "Workstation"]
[Black "Stockfish_23022721_x64_bmi2"]
[Result "*"]
[BlackElo "2000"]
[Time "11:25:51"]
[WhiteElo "2000"]
[TimeControl "0+300"]
[SetUp "1"]
[FEN "8/2p4p/3k1p2/pn3p2/PNp4p/r3Rp1P/2P2P2/BK6 w - - 0 1"]
[Termination "unterminated"]
[PlyCount "0"]
[WhiteType "human"]
[BlackType "human"]

*[/pgn]


And finally starting on move 2 in the main line:

[pgn][Event "Computer chess game"]
[Site "WORKSTATION-PC"]
[Date "2023.03.24"]
[Round "?"]
[White "Workstation"]
[Black "Stockfish_23022721_x64_bmi2"]
[Result "*"]
[BlackElo "2000"]
[Time "11:30:39"]
[WhiteElo "2000"]
[TimeControl "2700+15"]
[SetUp "1"]
[FEN "8/2p2p1p/5p2/pn1k4/P1p4p/r3Rp1P/2P2P2/BK6 w - - 0 1"]
[Termination "unterminated"]
[PlyCount "0"]
[WhiteType "human"]
[BlackType "human"]

*[/pgn]

I'm sure somebody like Peter Krug could do a much better job of fixing this study

[acase]

It looks like this study (2015) was derived from an earlier study (1988)

2015 study:

[pgn][Event "Shakhmatnaya Kompozitsia#22"]
[Site "?"]
[Date "2015.??.??"]
[Round "?"]
[White "Zemlyansky=Y"]
[Black "(+0414.48b1d6)"]
[Result "1-0"]
[SetUp "1"]
[FEN "8/2p2p1p/3k1p2/pn6/PNp4p/r3Rp1P/2P2P2/BK6 w - - 0 1"]
[PlyCount "319"]
[EventDate "2015.??.??"]

{HHdbV#423} 1. Nd5 $1 (1. c3 $2 Rb3+ 2. Kc1 Na3) (1. Re4 $2 Rxa4 2. Na6 Na3+ 3.
Kc1 Nxc2 4. Bxf6 Nb4 5. Nxb4 axb4 6. Rxc4 c5) 1... Kxd5 2. Rxa3 Nxa3+ 3. Kb2
c3+ $1 4. Kxa3 Kc4 5. Ka2 Kb4 6. Kb1 Kc4 7. Kc1 Kb4 8. Kd1 Kc4 9. Ke1 Kb4 10.
Kf1 Kc4 11. Kg1 Kb4 12. Kh1 (12. Kh2 {<or>}) 12... Kc4 13. Kh2 Kb4 14. Kg1 Kc4
15. Kf1 Kb4 16. Ke1 Kc4 17. Kd1 Kb4 18. Kc1 Kc4 19. Kb1 Kb4 20. Ka2 Kc4 21. Ka3
h6 22. Ka2 Kb4 23. Kb1 Kc4 24. Kc1 Kb4 25. Kd1 Kc4 26. Ke1 Kb4 27. Kf1 Kc4 28.
Kg1 Kb4 29. Kh2 Kc4 30. Kh1 Kb4 31. Kg1 Kc4 32. Kf1 Kb4 33. Ke1 Kc4 34. Kd1 Kb4
35. Kc1 Kc4 36. Kb1 Kb4 37. Ka2 Kc4 38. Ka3 h5 39. Ka2 Kb4 40. Kb1 Kc4 41. Kc1
Kb4 42. Kd1 Kc4 43. Ke1 Kb4 44. Kf1 Kc4 45. Kg1 Kb4 46. Kh2 Kc4 47. Kh1 Kb4 48.
Kg1 Kc4 49. Kf1 Kb4 50. Ke1 Kc4 51. Kd1 Kb4 52. Kc1 Kc4 53. Kb1 Kb4 54. Ka2 Kc4
55. Ka3 f5 56. Ka2 Kb4 57. Kb1 Kc4 58. Kc1 Kb4 59. Kd1 Kc4 60. Ke1 Kb4 61. Kf1
Kc4 62. Kg1 Kb4 63. Kh1 Kc4 64. Kh2 Kb4 65. Kg1 Kc4 66. Kf1 Kb4 67. Ke1 Kc4 68.
Kd1 Kb4 69. Kc1 Kc4 70. Kb1 Kb4 71. Ka2 Kc4 72. Ka3 f4 73. Ka2 Kb4 74. Kb1 Kc4
75. Kc1 Kb4 76. Kd1 Kc4 77. Ke1 Kb4 78. Kf1 Kc4 79. Kg1 Kb4 80. Kh2 Kc4 81. Kh1
Kb4 82. Kg1 Kc4 83. Kf1 Kb4 84. Ke1 Kc4 85. Kd1 Kb4 86. Kc1 Kc4 87. Kb1 Kb4 88.
Ka2 Kc4 89. Ka3 f6 90. Ka2 Kb4 91. Kb1 Kc4 92. Kc1 Kb4 93. Kd1 Kc4 94. Ke1 Kb4
95. Kf1 Kc4 96. Kg1 Kb4 97. Kh2 Kc4 98. Kh1 Kb4 99. Kg1 Kc4 100. Kf1 Kb4 101.
Ke1 Kc4 102. Kd1 Kb4 103. Kc1 Kc4 104. Kb1 Kb4 105. Ka2 Kc4 106. Ka3 f5 107.
Ka2 Kb4 108. Kb1 Kc4 109. Kc1 Kb4 110. Kd1 Kc4 111. Ke1 Kb4 112. Kf1 Kc4 113.
Kg1 Kb4 114. Kh2 Kc4 115. Kh1 Kb4 116. Kg1 Kc4 117. Kf1 Kb4 118. Ke1 Kc4 119.
Kd1 Kb4 120. Kc1 Kc4 121. Kb1 Kb4 122. Ka2 Kc4 123. Ka3 c6 124. Ka2 Kb4 125.
Kb1 Kc4 126. Kc1 Kb4 127. Kd1 Kc4 128. Ke1 Kb4 129. Kf1 Kc4 130. Kg1 Kb4 131.
Kh2 Kc4 132. Kh1 Kb4 133. Kg1 Kc4 134. Kf1 Kb4 135. Ke1 Kc4 136. Kd1 Kb4 137.
Kc1 Kc4 138. Kb1 Kb4 139. Ka2 Kc4 140. Ka3 c5 141. Ka2 Kb4 142. Kb1 Kc4 143.
Kc1 Kb4 144. Kd1 Kc4 145. Ke1 Kb4 146. Kf1 Kc4 147. Kg1 Kb4 148. Kh2 Kc4 149.
Kh1 Kb4 150. Kg1 Kc4 151. Kf1 Kb4 152. Ke1 Kc4 153. Kd1 Kb4 154. Kc1 Kc4 155.
Kb1 Kb4 156. Ka2 Kc4 157. Ka3 Kd4 158. Kb3 c4+ 159. Ka3 Kc5 160. Bxc3 1-0[/pgn]


1988 study:

[pgn][Event "64 Shakhmatnoye Obozrenye"]
[Site "?"]
[Date "1988.??.??"]
[Round "?"]
[White "Dolgov=V"]
[Black "(+0010.48a2c4)"]
[Result "1-0"]
[SetUp "1"]
[FEN "8/2p2p1p/5p2/p7/2k4p/P1p2p1P/K1P2P2/B7 w - - 0 1"]
[PlyCount "309"]
[EventDate "1988.??.??"]

{HHdbV#25714} 1. a4 Kb4 2. Kb1 Kc4 3. Kc1 Kb4 4. Kd1 Kc4 5. Ke1 Kb4 6. Kf1 Kc4
7. Kg1 Kb4 8. Kh2 Kc4 9. Kh1 Kb4 10. Kg1 Kc4 11. Kf1 Kb4 12. Ke1 Kc4 13. Kd1
Kb4 14. Kc1 Kc4 15. Kb1 Kb4 16. Ka2 Kc4 17. Ka3 h6 18. Ka2 Kb4 19. Kb1 Kc4 20.
Kc1 Kb4 21. Kd1 Kc4 22. Ke1 Kb4 23. Kf1 Kc4 24. Kg1 Kb4 25. Kh2 Kc4 26. Kh1 Kb4
27. Kg1 Kc4 28. Kf1 Kb4 29. Ke1 Kc4 30. Kd1 Kb4 31. Kc1 Kc4 32. Kb1 Kb4 33. Ka2
Kc4 34. Ka3 h5 35. Ka2 Kb4 36. Kb1 Kc4 37. Kc1 Kb4 38. Kd1 Kc4 39. Ke1 Kb4 40.
Kf1 Kc4 41. Kg1 Kb4 42. Kh2 Kc4 43. Kh1 Kb4 44. Kg1 Kc4 45. Kf1 Kb4 46. Ke1 Kc4
47. Kd1 Kb4 48. Kc1 Kc4 49. Kb1 Kb4 50. Ka2 Kc4 51. Ka3 f5 52. Ka2 Kb4 53. Kb1
Kc4 54. Kc1 Kb4 55. Kd1 Kc4 56. Ke1 Kb4 57. Kf1 Kc4 58. Kg1 Kb4 59. Kh1 Kc4 60.
Kh2 Kb4 61. Kg1 Kc4 62. Kf1 Kb4 63. Ke1 Kc4 64. Kd1 Kb4 65. Kc1 Kc4 66. Kb1 Kb4
67. Ka2 Kc4 68. Ka3 f4 69. Ka2 Kb4 70. Kb1 Kc4 71. Kc1 Kb4 72. Kd1 Kc4 73. Ke1
Kb4 74. Kf1 Kc4 75. Kg1 Kb4 76. Kh2 Kc4 77. Kh1 Kb4 78. Kg1 Kc4 79. Kf1 Kb4 80.
Ke1 Kc4 81. Kd1 Kb4 82. Kc1 Kc4 83. Kb1 Kb4 84. Ka2 Kc4 85. Ka3 f6 86. Ka2 Kb4
87. Kb1 Kc4 88. Kc1 Kb4 89. Kd1 Kc4 90. Ke1 Kb4 91. Kf1 Kc4 92. Kg1 Kb4 93. Kh2
Kc4 94. Kh1 Kb4 95. Kg1 Kc4 96. Kf1 Kb4 97. Ke1 Kc4 98. Kd1 Kb4 99. Kc1 Kc4
100. Kb1 Kb4 101. Ka2 Kc4 102. Ka3 f5 103. Ka2 Kb4 104. Kb1 Kc4 105. Kc1 Kb4
106. Kd1 Kc4 107. Ke1 Kb4 108. Kf1 Kc4 109. Kg1 Kb4 110. Kh2 Kc4 111. Kh1 Kb4
112. Kg1 Kc4 113. Kf1 Kb4 114. Ke1 Kc4 115. Kd1 Kb4 116. Kc1 Kc4 117. Kb1 Kb4
118. Ka2 Kc4 119. Ka3 c6 120. Ka2 Kb4 121. Kb1 Kc4 122. Kc1 Kb4 123. Kd1 Kc4
124. Ke1 Kb4 125. Kf1 Kc4 126. Kg1 Kb4 127. Kh2 Kc4 128. Kh1 Kb4 129. Kg1 Kc4
130. Kf1 Kb4 131. Ke1 Kc4 132. Kd1 Kb4 133. Kc1 Kc4 134. Kb1 Kb4 135. Ka2 Kc4
136. Ka3 c5 137. Ka2 Kb4 138. Kb1 Kc4 139. Kc1 Kb4 140. Kd1 Kc4 141. Ke1 Kb4
142. Kf1 Kc4 143. Kg1 Kb4 144. Kh2 Kc4 145. Kh1 Kb4 146. Kg1 Kc4 147. Kf1 Kb4
148. Ke1 Kc4 149. Kd1 Kb4 150. Kc1 Kc4 151. Kb1 Kb4 152. Ka2 Kc4 153. Ka3 Kd4
154. Kb3 c4+ 155. Ka3 1-0[/pgn]

Of course I'm sure some of you already were aware of that.

[DmitriyFrosty]

Truly remarkable study!