非定常系統 (Rheonomous)

居文君 (Jū Wénjūn) – 余泱漪 (Yú Yāngyī)
52nd Chinese Chess Championship; 兴化 (Xīnghuà), May 15, 2021
Two Knights Defence C55

1. e4 e5 2. Nf3 Nc6 3. Bc4 Nf6 4. d3 Be7 5. Nc3 d6 6. a4 0-0 7. h3 Be6 8. 0-0 Nxe4!? This may be a novelty, though a very natural reply. 9. Nxe4 d5 10. Neg5 dxc4 11. Nxe6 fxe6 12. dxc4 Qxd1 13. Rxd1 Bc5 14. Be3 Bxe3 15. fxe3 h6 16. Rd7 Rf7 17. Rxf7. Likewise after 17. Rad1 Raf8 the game would tend towards a draw. 17. ... Kxf7 18. Rf1 Ke8 19. Kf2 Ke7 20. Ke2 Rf8 21. Rb1 a5 22. c3 b6 23. Kd3

23. ... Nb8! A temporary Pawn sacrifice which should equalise for Black. 24. Nxe5 Rf2 25. c5 bxc5. Also worth considering was 25. ... Rxg2 26. b4 Rg5 with a very drawish position. 26. g4

26. ... Nd7? This is the move that loses the game. Best was 26. ... Rh2 27. Rf1 (27. h4 is also answered by 27. ... Ke8) 27. ... Ke8 28. Rf7 Nc6! with a drawish Knight ending. 27. Nc6+ Kd6 28. Nxa5 Nb6 29. Nc4+ Kc6. 29. ... Nxc4 40. Kxc4 Kc6 41. a5 transposes to the game.

30. a5! Nxc4. Of course the Rook endgame is hopeless for Black, but 30. ... Nc8 31. a6 does not offer any hope either. 31. Kxc4 Re2 32. a6 Kb6 33. Ra1 Ka7 34. Ra5 Rxb2 35. Rxc5 Kb6 (35. ... Kxa6 36. Rxc7+−) 36. Re5 Kxa6 37. Rxe6+ Kb7 38. h4 Ra2 39. Kd3 Rf2 40. Rg6 Rf7 41. e4 c6 42. e5 Kb6 43. Ke4 Kc5 44. h5 Kb5 45. Rd6 Kc5 46. Rd8 Re7 47. Rd4 Kb5 48. Kf5 c5 49. Rd1 Rf7+ 50. Ke6 Ra7 51. Kd6 Kc4 52. e6 Ra6+ 53. Kd7 Ra7+ 54. Ke8 Kxc3 55. e7 Ra2 56. Kd7 1 : 0.

By winning her last-round game against 余泱漪 (Yú Yāngyī), three-time Women’s World Chess Champion 居文君 (Jū Wénjūn) succeeded in gaining rating points, yet without depriving her opponent of his second title in a row. Photo: Chinese Chess Association.