Nash equilibrium

Tor Fredrik Kaasen – Aleksandra Yuryevna Goryachkina
23rd European Individual Chess Championship; Vrnjačka Banja, March 10, 2023
Slav Defence D12

1. d4 d5 2. c4 c6 3. Nf3 Nf6 4. e3 Bf5 5. Nc3 e6 6. Nh4 Bg6 7. Bd2 Nbd7 8. Qb3 Qb6 9. Nxg6 hxg6 10. Be2 Be7 11. h3. If 11. Rc1 then 11. ... g5! 12. Qxb6 axb6 13. a3 g4 14. g3 Kf8 15. Kf1 dxc4 16. Bxc4 b5 17. Bd3 e5 with good play for Black, Pogonina – Goryachkina, 68th Russian Women’s Chess Championship Superfinal, Satka 2018.

11. ... a6!? This has all appearances of being a counterintuitive innovation, but obviously Goryachkina must have had her reasons for it.
12. Qxb6 Nxb6 13. b3 0-0. Fearlessly castling into the semi-open h-file. Black could also adopt a dynamic waiting policy with ... Nb6-c8-d6.

14. g4 c5 (14. ... g5 15. h4!↑)
15. dxc5 Bxc5 16. cxd5. 16. g5 at once was to be considered, but 16. ... Nfd7 17. cxd5 exd5 would leave Black with quite a comfortable isolated Pawn position.
16. ... Nbxd5 17. Nxd5 Nxd5 18. Bf3 Rac8 19. Ke2

19. ... Ba3! 20. Bxd5 exd5 21. Kd3 f6 (21. ... Rc6 22. Bc1 Be7 23. Bb2 Rfc8=)
22. h4 Kf7 23. h5 gxh5. But not 23. ... g5? because of 24. f4! with troubles for Black.
24. Rxh5 Ke6 25. f4 Rc6 26. Rh7 Kf7 27. Rh5 Ke6 28. Rh7 Kf7 29. Rh5 ½ : ½.