Commentary: U.S. Women's Championship 2021, Round 9 (Krush - Nemcova)

This game features another ambiguous opening classification, since the database will tell you it's an English Opening (A10 ECO code), but one look at the board on move 7 will tell you that it's a Leningrad Dutch. GM Irina Krush as White kept her full intentions in the opening hidden until that point, but after her opponent WGM Katerina Nemcova committed to a full Leningrad setup, there was no reason not to play d4 and control the e5 square, especially after having done the early b3/Bb2 development.

From there Krush gains an small opening advantage, thanks to Black neglecting her development in favor of some premature demonstrations (7...Ne4 and 8...c5) that do not actually challenge White. Krush masterfully rides this advantage into the middlegame, although she seems to deliberately choose solid over sharper possibilities, in keeping with her general opening posture. Black's strategic weakness on d6 becomes the key feature of the game, leading White eventually to gain tactically. That said, it's worth observing that even when behind and under pressure, opportunities often present themselves - see move 31 - for the worse-off player to rally. Normally this is a feature of long endgames as well, but Krush never lets her opponent back into the game after entering a R+B v R endgame, which is instructive to see.

I did not post an evaluation chart this time, because the one generated was misleading and displays Black achieving equality (and more) around move 22, whereas longer engine analysis shows a persistent White plus. This sometimes happens with the "snapshot" type evaluation function of various programs/sites, so you should always be somewhat skeptical of anything insta-generated by a computer, until you can perform your own analysis.

[Event "U.S. Women's Chess Championship 2021"] [Site "http://www.chessbomb.com"] [Date "2021.10.16"] [Round "09"] [White "Krush, Irina"] [Black "Nemcova, Katerina"] [Result "1-0"] [WhiteElo "2429"] [BlackElo "2331"] [EventDate "????.??.??"] [ECO "A10"] [PlyCount "135"] [BlackClock "0:03:47"] [BlackFideId "322750"] [TimeControl "5400+30"] [WhiteClock "0:25:41"] [WhiteFideId "2012782"] 1.c4 f5 2.g3 Nf6 3.Bg2 g6 {committing to the Leningrad Dutch formation.} 4.b3 {this commits the bishop to develop to b2 and then to immediately fight its Black counterpart on the long diagonal, including for the key square e5.} 4...Bg7 5.Bb2 O-O 6.Nf3 d6 7.d4 {White finally commits her pawn to d4, but only after Black was threatening to get in ...e5. We now have a reasonably standard Leningrad Dutch position, where White has chosen an early b3/Bb2 development scheme.} 7...Ne4 {This is the third most played choice in the database, although the standard ...c6 and ...Qe8 are more popular. It doesn't score very well for Black, though, and seems premature.} 8.Nbd2 {the usual location for this knight in the variation, leaving the Bb2 unblocked.} 8...c5 {Black challenges the center, but is falling behind in development.} ( 8...Nc6 $5 ) 9.Qc2 {the usual spot for the queen, protecting b2 and pressuring e4.} 9...cxd4 {this exchange helps White, who has everything covered and more pieces developed.} 10.Nxd4 Qb6 11.e3 {a solid choice preserving White's central edge and restraining f5-f4.} ( 11.Nxe4 $5 {is the engine's preference and here seems a relatively simple path to advantage, limiting Black's counterplay. The knight is inadequately supported on e4, a fact which informs the next few moves of the game.} 11...Bxd4 ( 11...fxe4 {this cedes the pawn for no real compensation.} 12.Qxe4 Qa5+ 13.Kf1 $16 {the White king is well-protected and the Rh1 can still participate in the game by supporting an h-pawn push.} ) 12.Bxd4 Qxd4 13.Nc3 $16 {and after some straightforward exchanges, White has a significant lead in development and active play in both the center and kingside against Black's weak squares.} ) 11...e5 {the rule in the Leningrad Dutch is to play ...e5 whenever Black can get away with it. Here it is a little premature, because of the unstable Ne4.} ( 11...Nf6 {the engine assesses the knight retreat is best.} ) 12.Nb5 {this avoids complications and leaves White with a small plus.} ( 12.Nxe4 {immediately still works, but is messier than in the previous variation, since now the Nd4 is attacked by a pawn.} 12...exd4 13.Ng5 {and now} 13...dxe3 $2 {looks dangerous, but it is Black that is in trouble after something like} 14.Bd5+ Kh8 15.O-O-O exf2 16.Qe2 $18 {White is threatening to penetrate with Qe7 and Nf7 cannot be defended against, so Black will have to give up the exchange.} ) 12...a6 {the obvious choice, kicking the knight.} 13.Nxe4 {now White pulls the trigger on the Ne4.} 13...axb5 14.Nc3 bxc4 15.Nd5 {an excellent outpost for the knight.} 15...Qd8 16.Qxc4 Be6 {Black starts repairing her development, While pinning the knight and blocking White's tactical ideas along the diagonal.} 17.O-O Nc6 18.Rfd1 {naturally White wants to exert latent pressure on the d-file, eyeing the backward d6 pawn.} 18...Rf7 {the immediate ...e4 may have been better, waiting to commit the rook to a course of action.} 19.b4 {White intends to mobilize her queenside pawn majority.} 19...e4 {cutting off the Bg2 and opening up the long diagonal.} 20.Bxg7 {the exchange is best, as otherwise White will have to take time to defend the bishop.} 20...Kxg7 21.a4 {White could have done some other things here, for example immediately reactivating the bishop with Bf1. The engine points out a nice tactical maneuver possibility by Black that could have lead to equality, in response.} 21...Ne5 $6 {now White's queen gets out of the pin and is still powerfully centralized.} ( 21...Qf6 $5 {the point being that} 22.Nxf6 Bxc4 23.Nd5 Bb3 {and Black is fine, being able to effectively trade the weak d-pawn for one of White's queenside pawns. Otherwise, Black as a follow-up can play ...Qe5 and/or trade on d5 and be equal.} ) 22.Qd4 $16 Bxd5 23.Qxd5 Rd7 {apparently an idea behind the original ...Rf7, but Black is getting cramped defending her weaknesses.} 24.Bf1 Qg5 $6 {superficially aggressive but Black does not have an attack. White calmly defends, allowing Black to overcommit her forces, then strikes back in the center and queenside.} ( 24...Qg8 ) 25.Be2 h5 26.h4 Qe7 27.Kg2 {covering some holes and allowing the first rank to be cleared.} 27...Rc8 28.Rd2 {intending to double rooks on the d-file.} ( 28.Rac1 {seems more straightforward. Exchanging off a pair of rooks would be advantageous to White, who will have a winning 2-1 queenside majority in the endgame. If Black avoids the trade, then White has the file and can start pushing the pawns anyway.} ) 28...Qf7 29.Qd4 {White has the better queen so avoids the trade.} 29...Qf6 30.Rad1 d5 {at least this gives Black a little more room for maneuver.} 31.a5 ( 31.b5 $5 {would prevent ...Nc6.} ) 31...Rcd8 $2 {going for static defense, which does not work.} ( 31...Nc6 {gains a tempo and solves some of Black's problems in the center. For example} 32.Qb6 Ne7 $14 {and Black is close to equality, as the knight can hold d5 by itself, freeing up both rooks.} ) 32.b5 {now the Ne5 is out of the important central fight.} 32...Nf7 33.Qc5 Qd6 34.Qxd6 {White chooses to simplify closer to a winning endgame.} 34...Rxd6 35.a6 bxa6 36.bxa6 $18 {The Be2 plays a key supporting role for the pawn, even if not active otherwise.} 36...Ne5 {the knight tries to get back in the fight, but it is too late.} 37.a7 {passed pawns must be pushed!} 37...Nc6 38.Rxd5 $1 {White finds the correct tactical follow-up. With the pawn about to queen, Black cannot take twice on d5.} 38...Rxd5 39.Rxd5 Ra8 40.Rc5 Nxa7 41.Ra5 {the knight is now inevitably lost, since White can bring around the bishop to attack the Ra8.} 41...Kh6 42.Ra6 Kg7 43.Bc4 Rc8 44.Rxa7+ Kf6 {the game is now a theoretical win for White. Black knows that it still takes practical skill to win the R+B v R ending, so she keeps playing. Krush is up for it, however.} 45.Ra6+ Kg7 46.Bb5 Rb8 47.Ba4 {the bishop is now shielded from the rook's attention, as ...Rb4 is met by Be8, winning the pawn.} 47...Kf7 {the king is tied to the defense of the g-pawn.} 48.Rd6 Kg7 49.Kf1 {White decides to march her king around, which Black permits. However, she cannot really stop the idea.} 49...Kf7 ( 49...Rb1+ 50.Rd1 ) 50.Ke2 Rb4 51.Bc2 {bringing it back as a shield for the king.} 51...Rb2 52.Kd2 Kg7 53.Kc3 Ra2 54.Rb6 {note how Black's rook is beginning to get cramped.} 54...Ra1 55.Rb1 {naturally Black has zero chances if she gives up the rook.} ( 55.Rb7+ {it's interesting to see how White could have been more aggressive if she chose. The problem for Black is that her king is potentially vulnerable, without g5 and h4 as escape squares. So for example} 55...Kf6 56.Kd4 Rf1 $2 57.Bb3 {and Black has to give up material.} ) 55...Ra2 56.Rb2 Ra3+ 57.Bb3 {a good opportunity to place the bishop on this key diagonal.} 57...Ra1 58.Ra2 Rb1 59.Bc4 Rd1 60.Ra6 Rd8 61.Bb5 Kf7 62.Ra7+ Ke6 63.Rg7 Kf6 64.Rd7 Ra8 65.Kd4 {the centralized king is the significant difference from when the piece maneuvering all began. White is patiently constricting Black's maneuvering room and bringing up her king as a strong reinforcement.} 65...Ke6 66.Kc5 Ra5 $2 {this allows a tactical finish, forcing the rook trade.} 67.Rd6+ Kf7 68.Ra6 1-0