[Event "Krug-50 JT"] [Site "?"] [Date "2017.??.??"] [Round "?"] [White "Rusz, Árpád"] [Black "(Study 142)"] [Result "1-0"] [Annotator "1st Sp. Pr. (after Bourzutschky & Konoval)"] [SetUp "1"] [FEN "8/2R4B/4k3/3n2K1/1Pp2rN1/2Pb4/8/8 w - - 0 1"] [PlyCount "77"] [EventDate "2017.??.??"] 1. Bg8+ (1. Rc6+ $2 Kd7 {In the following two variations black saves the game by sacrificing the knight or the rook. This provides some comfort for the fact that in the main line these two black pieces are captured on their initial squares.} (1... Ke7 $2 2. Ne3 $1 {knight sacrifice} Nxe3 3. Kxf4 $18) 2. Rc5 ( 2. Ne5+ Ke7 3. Nxd3 cxd3 4. Bxd3 Nxb4 $1 {knight sacrifice} (4... Rf3 $2 5. Be4 Rg3+ 6. Kh4 Rxc3 7. Bxd5 $18) 5. cxb4 Rxb4 $11) 2... Rxg4+ $1 {rook sacrifice} 3. Kxg4 Nf6+ 4. Kf4 Nxh7 (4... Bxh7 $2 5. Ke5 $1 Ng4+ 6. Kd4 $18) 5. b5 Nf8 $1 6. Ke5 Ng6+ 7. Kf6 Kd6 8. Rc6+ Kd7 9. Rc5 Kd6 {positional draw}) 1... Kd6 2. Rc6+ $1 {rook sacrifice} (2. Bxd5 $2 Rf5+ 3. Kh4 Kxc7 $11) 2... Kxc6 3. Bxd5+ Kd6 $1 {The black king triangulates!} (3... Kxd5 4. Kxf4 {black is in zugzwang} Be2 (4... Ke6 5. Ne5 Be2 6. Ke4 $18) 5. Ne3+ Ke6 6. Ke4 $18) 4. Kxf4 Kxd5 { Cyclic zugzwang - WTM. In order to win, white must reach the same position but with black to move. The shortest manoeuvre to pass the move to black lasts 35 moves! All moves from the cycle are unique optimal moves.} 5. Ne3+ (5. Nf2 $6 Be2 6. Kf5 $6 Bd3+ 7. Kf6 $2 Bc2 $1 8. Ke7 Ba4 $11) 5... Ke6 6. Nd1 Kd5 7. Nb2 {White threatens to bring the knight to c5.} Bc2 $1 8. Kg5 Bd3 (8... Ke4 9. Kf6 Kd5 10. Ke7 Bf5 11. Kd8 $18) 9. Kf6 (9. Na4 $2 Ke5 $11) 9... Kd6 {White should bring the knight to a5 before he continues the king manoeuvre.} 10. Nd1 $1 ({ The shortest path to a5 via a4-c5-b7 doesn't work:} 10. Na4 $6 Be4 11. Nc5 Bc6 $1) ({If the king starts the manoeuvre too soon, its knight gets stuck on b2:} 10. Kf7 $6 Bf1 11. Ke8 Be2 12. Kd8 Kc6 $1 13. Ke7 Kb5 $1 {Now, in order to win, white has to free its knight...} 14. Ke6 Bg4+ 15. Ke5 Bf3 16. Kf4 Be2 17. Ke3 Bh5 18. Kd2 Bg6 19. Ke2 $1 {Quicker than the immediate 18.Nd1. It is better to lure the bishop to f5 first using a triangulation.} Bh5+ 20. Ke3 Bg4 21. Kd2 Bf5 22. Nd1 {Now the knight is free but also the black king!} Kc6 23. Ke3 Kd5 24. Nb2 Bg6 25. Kf4 Bc2 {and we have returned to a previous position from the main line}) 10... Be4 11. Ne3 Bd3 12. Ng4 Be2 13. Ne5 Bd3 14. Nf7+ Kd5 {This move blocks the a8-h1 diagonal allowing the knight to go to b7.} (14... Kd7 15. Ke5 $18) 15. Nd8 $1 Kd6 16. Nb7+ Kc7 17. Na5 $1 ({Moving immediately to c5 is wrong:} 17. Nc5 $6 Kd6 {and the white king cannot move to f5.}) 17... Kd6 18. Kf7 Kd7 19. Nb7 $1 {Black is in zugzwang!} Be2 ({The bishop cannot move to the big diagonal:} 19... Be4 20. Nc5+ $18) 20. Kf6 Kc7 21. Nc5 Kd6 22. Kf5 {The bishop was not on d3!} Kd5 23. Kf4 Bf1 {[%cal Rc5d7,Rd7f6,Rf6e4,Re4c5,Yd5d6, Yd6e6,Ye6d5] This is a new cyclic zugzwang position! White will lose a tempo by a square-shaped manoeuvre (Nc5-d7-f6-e4-c5) while the black king triangulates (Kd5-d6-e6-d5).} (23... Bd3 24. Nxd3 cxd3 25. Ke3 Kc4 26. Kd2 $18) 24. Nd7 ({It is too early to bring the knight to a4:} 24. Na4 $2 Be2 25. Ke3 Bd3 {White is in zugzwang!} 26. Nb6+ Kc6 27. Nc8 Kc7 28. Ne7 Kd6 29. Ng8 Ke5) 24... Kd6 25. Nf6 Ke6 26. Ne4 Kd5 27. Nc5 Be2 28. Na4 $1 Bd3 29. Ke3 {Black is in zugzwang! The bishop has to leave the good square from which it controls the b1-h7 diagonal.} Bf1 30. Nb6+ Ke5 ({In the following variation we can see the drawback of leaving the b1-h7diagonal:} 30... Kc6 31. Nc8 Kc7 32. Ne7 Kd6 33. Ng6 $1 Kd5 (33... Bd3 34. Nf4 $18) 34. Kf2 Bd3 35. Nf4+ Ke4 36. Nxd3 Kxd3 37. b5 $18) 31. Kf3 $1 {This is a waiting move to lure the bishop to d3!} ({ The immediate Nd7 is refuted by Ke6.} 31. Nd7+ $6 Ke6) 31... Bd3 32. Nd7+ Kd6 ( {Ke6 is not that strong anymore:} 32... Ke6 33. Nc5+ Kd5 34. Nxd3 cxd3 35. Ke3 Kc4 36. Kd2 $18) 33. Nc5 {By attacking the bishop, white wins a crucial tempo. The black king cannot go back to the fifth rank, so the bishop must control e4. That means it has to leave the d3-f1 diagonal.} Bf5 {The bishop also takes under control the important d7 square.} 34. Kf4 $1 (34. Ke3 $6 {would throw away all the progress we have done so far.} Ke5 {[%eval 32546,0]} 35. Na4 Bd7 36. Nb2 Be6 37. Kd2 Bd5 38. Nd1 Be4 39. Ne3 Bd3 40. Ng4+ Kf4 41. Nf6 Bf5 42. Nd5+ Ke4 43. Ne3 Be6 44. Nc2 Bg4 45. Nd4 Ke5 46. Kc1 Kd6 47. Kc2 Bh5 48. Nf5+ Ke5 49. Ne3 Bf7 50. Kb2 Ke4 51. Nc2 Bh5 52. Nd4 Kd5 53. Ka3 Bd1 54. Nf5 Kc6 55. Ne3 Bb3 56. Kb2 Kc7 $1 57. Nf5 Ba4 58. Kc1 Kd7 59. Nh6 Kd6 60. Kd2 Ke5 61. Ke3 Bd1 62. Nf7+ Ke6 63. Ng5+ Ke5 64. Ne4 Bc2 65. Nd2 Bd3 66. Nf3+ Kd5 67. Nh2 Bc2 68. Kf4 Bb1 $1 69. Ng4 Bd3 {and we have returned to the cyclic zugzwang position from the main line}) 34... Bg6 35. Ke3 Kd5 (35... Ke5 36. Nd7+ {now that the bishop has left f5 this move works} Kd5 37. Nb6+ $18) 36. Nd7 {The threat is Nb6+} Bd3 37. Nf6+ Ke5 38. Ng4+ Kd5 39. Kf4 {cyclic zugzwang - BTM} 1-0