Commentary: 2022 U.S. Women's Championship, Round 10 (Foisor - Yan)

I've been both pleased and intrigued to see the variety of openings played at the various U.S. Championships and examined on the blog. Here we have a noble try at a Colle-Zukertort System, courtesy of WGM Sabina Foisor, which is something of a cult favorite among club players. Her opponent FM Ruiyang Yan knows the main line for Black and ends up with a comfortable middlegame position, with White's attempt at an attacking setup banished. However, there are some tricky tactical possibilities that White passed up that are worth examining. The main conflict occurs after Black wins a pawn and then White sacrifices the exchange in an apparent attempt to avoid a tortured losing endgame. White's play is eventually justified, once again proving the "all rook endgames are drawn" chess saying.

[Event "U.S. Women's Chess Championship 2022"] [Site "Chess.com"] [Date "2022.10.15"] [Round "10"] [White "Foisor, Sabina-Francesca"] [Black "Yan, Ruiyang"] [Result "1/2-1/2"] [ECO "D05"] [WhiteElo "2203"] [BlackElo "2220"] [Annotator "ChessAdmin/Dragon 3.2"] [PlyCount "161"] [EventDate "2022.??.??"] [TimeControl "5400+30"] 1. d4 Nf6 2. Nf3 e6 3. e3 d5 4. Bd3 c5 5. b3 {the Colle-Zukertort system.} Nc6 6. O-O Bd6 7. Bb2 {the classic move. Interestingly, Bb5 is now much more popular.} O-O 8. a3 {keeping the Black knight out of b4. However, this is slow and scores worse in the database than Bb5 (again) or developing immediately with Nbd2.} b6 {Black has to prepare the development of her light-square bishop.} 9. Nbd2 Bb7 10. Ne5 {the classic idea, posting up the knight on e5 and then gaining space on the kingside for an attack. White would welcome an exchange on e5, gaining space and kicking the Nf6 away with an occupying pawn.} Ne7 {this move does multiple things, increasing Black's control of e4 by getting out of the way of the Bb7, and preparing to go to f5 later.} 11. f4 {we now have a very Stonewall-like structure for White, with the difference of a pawn on a3 instead of c3.} Ne4 {for similar reasons as above, Black would welcome an exchange of the knight on e4.} 12. Qe2 {normally the best place for the queen, protecting the weak e3 pawn, forming a battery on the f1-a6 diagonal, connecting the rooks, and giving the option later of perhaps moving along the 2nd rank.} Rc8 {Black now has a classically solid position, with an obvious plan of expanding on the queenside and down the c-file.} 13. dxc5 {this scores well practically, but only if Black does not take with the knight.} (13. Nec4 $5 {is a tactical trick that results in equality, which is probably not what White wants in the first place, however. The main point is} dxc4 14. Bxe4 Bxe4 15. Nxe4 $11) 13... Bxc5 {this lets White off the hook.} (13... Nxc5 $17 {followed by ...Nxd3 exchanges off a key attacking piece for White and leaves Black with the most play.}) 14. b4 $11 {this now gains White both some space and time, by kicking the bishop.} Bd6 15. Nb3 {it's unclear why White chose this, as the b3 square has no advantage to it.} (15. Ndf3 {would be more standard.} Nf5 (15... f6 $6 {here has a tactical drawback, which is} 16. Nd4 $1 $14) 16. g4 {would be the standard reaction.}) 15... Nf5 16. Nd4 (16. g4 {here is not as good, with ...Nh4 now possible, among other responses.}) 16... Nxd4 17. Bxd4 f6 {a standard resource when fighting a Stonewall, as the f-pawn advance cannot be taken advantage of now.} 18. Nf3 Qc7 19. Bb2 $11 {proactively withdrawing, so that the pawn advance ...e5 would not come with tempo. By this point, White's attempt at an attacking setup has been rebuffed, but Black is unable to target any weak points either.} a5 20. Nd4 {targeting the now-weak e6 square.} Qd7 {perhaps not the best square for the queen, as it can become a target here.} 21. Rf3 {this is over-ambitious and also misses an opportunity to complicate Black's life with an f-pawn advance.} (21. f5 $5 e5 (21... exf5 22. Nxf5 $16 {White's kingside attacking chances are now revived, plus White has the prospect of picking up the two bishops.}) 22. Ne6 {the knight does look a little precarious here, but it should be all right:} Rfe8 23. Rad1 {creating tactics against the queen along the d-file} axb4 24. axb4 Qe7 25. Bxe4 dxe4 26. g4 $11) 21... axb4 {Black seizes the opportunity to win a pawn, without White having full compensation.} 22. axb4 Bxb4 23. Bb5 Qf7 $17 {White now has a bit of initiative on the kingside, but not much else for the pawn.} 24. f5 {now this comes with Black in better shape on both the queenside and kingside, than on move 21.} exf5 25. Nxf5 Kh8 {not necessary, but prudent nonetheless to get off the a2-g8 diagonal.} 26. Rh3 (26. Bd3 $5 {would move the bishop back to a more significant diagonal, where it could assist in the center or the kingside. The text move looks aggressive but is not a threat.}) 26... Rc7 {this subtle move clears c8 for the bishop, which now sees the Nf5 and Rh3 lined up on the diagonal.} 27. Rf1 Bc8 28. Bd3 {again, a good idea applied late.} Bc3 $6 {this preserves Black's existing advantage, but is a good idea played too early.} (28... g6 $1 29. Nh6 Qe7 30. Rh4 Bc3 31. Bxc3 Rxc3 $19 {and Black has a dominating position in the center.}) 29. Bxc3 Rxc3 30. Rh4 Bxf5 31. Rxf5 g6 {in contrast with the above variation, Black's pieces are more constrained and the strong light-square bishop is gone.} 32. Rxd5 $6 {White chooses to sacrifice the exchange, perhaps seeing a dull endgame squeeze in her future.} (32. Bxe4 dxe4 33. Rf2 $17 {with a depressing endgame.}) 32... Qxd5 33. Bxe4 Qg5 34. Rh3 $19 {the two Black rooks should triumph here, given the wide-open board and two weak White pawns to target on open files.} f5 35. Qd2 Qf6 36. Bd3 Ra3 (36... Rfc8 $5 {would seem to be the natural follow-up to ...f5, as the f-pawn no longer needs the extra piece support.}) 37. Qb4 Ra1+ 38. Kf2 Ra5 39. Rf3 Rc5 {Black is exclusively moving this rook around, which can't be good. White starts to take advantage of this.} 40. g4 {using the pin on the Qf6.} Qd6 41. Qb2+ Kg8 42. gxf5 {while this is still bad for White, she is at least successfully opening lines against Black's king.} Qxh2+ 43. Kf1 Qh1+ 44. Ke2 Qg2+ 45. Rf2 Qc6 46. Qa2+ Kg7 47. Qa1+ Qf6 48. Qa7+ Rf7 {putting an end to the queen harassment.} 49. Qb8 Rfc7 50. Kf1 {getting out of the way of the Rf2} g5 {this is still good for Black and prevents further opening of files, but will allow White some counterplay in the center.} 51. e4 Re7 52. Kg2 {correctly moving the king towards blocking Black's pawns.} Rce5 53. Rf1 Rxe4 {attempting to give back material and simplify into a more clearly won endgame.} (53... h5 $1 {is also a good idea, as passed pawns must be pushed! White has successfully established a static center based on the light-square pawn chain, but Black can mobilized her two connected passed pawns and still win.}) 54. Bxe4 Rxe4 {now we will get to see how the "all rook endings are drawn" saying applies in practice.} 55. Qb7+ Re7 56. Qf3 Rc7 {so far so good for Black.} 57. Qd3 Qc6+ {Black is still OK, but now the f-pawn is potentially mobile for White.} (57... Rc3 $1) 58. Kg1 Rd7 $6 {Black evidently missed White's f-pawn thrust.} 59. f6+ $1 $11 {the game is now a draw with best play, according to the engine. Black's king is too exposed and the advanced f-pawn too much of a threat for Black to make progress.} Kf8 60. Qg3 $2 (60. Qh3 $5 {this is more restrictive, threatening the Rd7 and to penetrate on the h-file.} Qc5+ 61. Kh1 $11) 60... Qc5+ {Black can now win again.} 61. Rf2 $2 {inviting Black's next.} Rd1+ 62. Kh2 Qd6 63. Qxd6+ Rxd6 {we now go back to the "all rook endings are drawn" line.} 64. f7 Rc6 65. Kg1 h5 {correctly mobilizing her passed pawn majority.} 66. Rf5 Rxc2 $2 {incorrectly allowing White's rook too much scope.} (66... Rc5 $1 $19 {it's much more important to preserve the two connected passed pawns.}) 67. Rxg5 Rc5 68. Rg6 {the only move. Now if the f- and b-pawns are exchanged off, the rook pawn cannot win for Black. This fact drives the next sequence.} b5 69. Rf6 b4 70. Rb6 Rc4 71. Rb7 Rf4 72. Kg2 {the draw is now apparent, with White's rook in a commanding position behind the b-pawn.} h4 73. Kh2 Kg7 74. Kg2 Rc4 75. Kh2 Rf4 76. Kg2 b3 77. Rxb3 Kxf7 78. Rf3 h3+ 79. Rxh3 Rf6 80. Rf3 Rxf3 81. Kxf3 1/2-1/2