Wesley So won a sacrificial game for the ages while Varuzhan Akobian was gifted a victory in Round 9.

A brilliant victory by Wesley So in Round 9 of the United States Championship was almost overshadowed later on by a terrible blunder by Fabiano Caruana that allowed Varuzhan Akobian to keep pace with So in the race for the title. They each have 6 points

Meanwhile, Alexander Onischuk continued his career revival as he beat Hikaru Nakamura to stay within striking distance of the leaders. He has 5.5 points.

A further half point back is Yaroslav Zherebukh, who beat Caruana in Round 7. Incredibly, Caruana and Nakamura, who were thought to be So’s primary rivals before the tournament began, are officially out of contention; they each have 4.5 points.

In the Women’s Championship, Sabina-Francesca Foisor and Nazi Paikidze remained in joint first, with 6 points apiece, after they drew in 30 moves. Irina Krush spoiled her opportunity to catch the leaders when she failed to convert a pawn-up ending against Carissa Yip. Krush is now tied for third with Anna Zatonskih, who dispatched Maggie Feng’s offbeat opening.

The two championships are being held at the Chess Club and Scholastic Center of Saint Louis. It is the ninth consecutive year that the club has hosted both events. The open tournament, a round-robin with 12 players, has a prize fund of $194,000. The women’s tournament, which is also a 12-player round-robin, has a prize fund of $100,000.

Although So’s scintillating performance was overshadowed by the shocking losses of the other two members of the United States’ “big three,” it was one of the finest victories in United States Championship history.

Jeffery Xiong vs. Wesley So
US Championship | Saint Louis USA | Round 9.1 | 07 Apr 2017 | ECO: E05 | 0-1
1. d4 Nf6 2. c4 e6 3. g3 d5 4. Bg2 Be7 5. Nf3 O-O 6. O-O dxc4 7. Qc2 a6 8. a4 Bd7 9. Rd1 Bc6 10. Nc3 Bxf3 11. Bxf3 Nc6 12. Bxc6 bxc6 13. Bg5 Rb8 14. e3 c5 15. dxc5 Qe8 16. Rd4 Nd7 This is the first in the game that had not been played before. So improves on a position played just once before, in 2012 between two strong Russian grandmasters: Sanan Sjugirov and Ilia Smirnov. In that game, Black played
16... Rb4 and the game eventually ended in a draw. So's continuation is the engine's top choice.  )
17. Bxe7 Qxe7 18. c6? A blunder which was undoubtedly an oversight: Xiong did not foresee So's 21st move. If he'd sensed the impending sacrifice, there is no way he would have entered this line.
18. f4 Is generally not a move that White wants to play, but in this position, it is necessary to prevent the knight from invading via e5.  )
18... Ne5 19. Qe4 Qc5 20. Nd5
20. f4 Ng4 Is still an excellent position for Black, since the exposed kingside offers great opportunities to attack.  )
20... Nd3 Xiong was hoping for
20... exd5 21. Qxe5 Qxc6 22. Rxd5 After which White stands better.  )
21. Nxc7 Nxf2! In his mental calculations, Xiong must have weighed the consequences of the following line:
21... Rxb2 22. Rxc4 Nxf2  )
22. Kxf2 Xiong already was on his back foot, but this move loses without much of a fight. When a player is caught by surprise, it is imperative to play the most challenging continuation. In tactical melees - particularly those with sacrificed material - there is always a possibility that the opponent might miscalculate.
22. Nxa6 Was absolutely required if Xiong was going to fight off So's attack. There are just so many complicated lines!
22... Qg5 To emphasize just how chaotic this position is, here is a sample variation:
...  23. Qf3 Rxb2 24. c7 Remains tricky. Black must be much better, if not winning, but the pawn on c7 is scary.  )
22... Rxb2+ 23. Kf1 Qh5 24. Qg4 Qxh2 25. Qf3 c3 26. Rc1 e5! An easy move to miss, since it feels a little slow. Yet, the rook on d4 is overloaded. If the rook remains on the d-file, Black pushes e5-e4 with a winning attack because the White queen absolutely must stay on f3 to cover checkmates on f2 and h1. If the rook swings along the fourth rank...
27. Rh4
27. Rc4 The path to victory for Black after this move is the reason I believe this was home preparation. So has not lost a game in forever, but the following sequence would have to be fully mapped out in order to justify Black's play. This variation is simultaneously absurd and beautiful.
27... Rfb8 28. Nd5 Rf2+!! 29. Qxf2 Qh1+ 30. Qg1 Qxd5 31. R4xc3 Rb2 32. e4 Qd2 33. R3c2 Rxc2 34. Rxc2 Qd1+ 35. Kg2 Qxc2+ 36. Kh3 Qxc6  )
27... Qd2 28. Rd1 Rd8!! What a shot.
29. Nd5 The queen is immune, since
29. Rxd2 Rdxd2 leads to an unstoppable back rank checkmate.  )
29... Rxd5 30. Rd4 Rxd4 31. exd4 Qxd1+ Xiong had enough: 32. Qxd1 c2 followed by Rb1 allows Black to queen first, and with check.

Whereas Xiong went down quickly, Nakamura, who was outplayed early on, clawed back into his game against Onischuk, the 2006 champion. The opening went awry for Nakamura and the four-time champion jettisoned a couple of pawns in the hopes of obtaining sufficient counterplay. Just after the time control Nakamura halved his pawn deficit, but Onischuk’s extra pawn kept him firmly in control. It appeared Nakamura had a strong defense in place, but Onischuk’s persistence paid off.

Hikaru Nakamura vs. Alexander Onischuk
US Championship | Saint Louis USA | Round 9.3 | 07 Apr 2017 | ECO: D35 | 0-1
Ne7 Black is better because of his extra pawn. In addition, his bishop is better than a knight in the endgame because it has much longer range, and it can attack both sides of the board at once. Onischuk's bishop greatly limits the scope of Nakamura's knights.
52. b4? Whether or not this pawn thrust makes the position objectively lost for White, it does create an impossible defensive task under time pressure.
52... a4 Onischuk wisely keeps as many pawns on the board as possible. Now a3 is a permanent weakness.
53. Nd4 Kd7 54. Ke2 Bd5 55. Nb5 Kc6 56. Nc3 b5 57. Kd3 Nf5 58. Nd1 Kd6 59. Nc3 Bc6 60. Nce4+ Ke7 61. Ng5 Kf6 62. Nge4+ Ke7 63. Ng5 Bg2 64. Nge4 Ke6 65. Nf2 Kd5 66. Nd1 Nd6 67. Nf2 Nc4 Onischuk wisely forces the knight trade.
68. Nxc4
68. Nb1 Bf1+ 69. Kc3 Be2 Leaves Nakamura with zero useful moves. Onischuk's king now infiltrates easily.  )
68... Bf1+ The point! Nakamura can no longer fend off the enemy king.
68... bxc4+ would not have made sense. There is no reason to hand your opponent a passed pawn.  )
69. Kc3 Bxc4 70. Nh3 Ke4 71. Kd2 Be6 72. Ng5+ Kd5 73. Nf3
73. Kc3 Does not delay the inevitable. After
73... Bf5 The bishop dominates the knight and Onischuk's king would break through.  )
73... Bg4 74. Nh4 Ke4 75. Ke1 Ke3

It was Onischuk’s second straight win.

The final game of the round was Akobian versus Caruana. Akobian had a slight edge for the first thirty moves, after which he played quite poorly in mutual time trouble. Caruana picked off one pawn and then a second, reaching the second-time control with unopposed passed pawns on the queenside. 

Varuzhan Akobian vs. Fabiano Caruana
US Championship | 0:01:33-0:00:33 | Round 10 | 07 Apr 2017 | ECO: A46 | 1-0
Qe5

Normally a surplus of two pawns is more than enough to win. But Caruana is clearly out-of-form and he inexplicably gave away his b-pawn as the commentary team of Maurice Ashley, Jennifer Shahade, and Yasser Seirawan looked on in bewilderment. Still, the defending champion retained good winning chances. Akobian’s stubborn resistance forced Caruana to exchange his c-pawn for the f-pawn. Then Caruana suffered one of the worst blunders of his career.

Varuzhan Akobian vs. Fabiano Caruana
US Championship | 0:01:33-0:00:33 | Round 10 | 07 Apr 2017 | ECO: A46 | 1-0
50. Rb1 Qe6? Instead,
50... c4 was simple and strong. Both queenside pawns will be protected through tactical means:
51. Nd4 Qd6 52. Rc1 c3 53. Qb3 Again the pawn is immune:
...  Nd5 And winning the game from this position should be a cinch for a player in the top five in the world.  )
51. Nc7 Qd7 52. Qxb6 c4 53. Nb5 Rd1+ 54. Rxd1 Qxd1+ 55. Kh2 Qd5 Keeping the queen in an aggressive position was much better. Akobian might not have had a better option than to trade queens, but
55... Qd2 56. Qd4 Qxd4 57. Nxd4 Nd5 It feels as if Black has enough of an edge in this position to win. The c-pawn ties down the White king and knight. Caruana would only have had to play straightforward moves like f5, Kf6-e5 and eventually f4. For example
58. Kg1 Kf6 59. Kf1 Ke5 60. Ke2 f5 61. Kd2 c3+ 62. Kc2 f4  )
56. Nd4 Now Caruana's queen is locked out. Akobian has set up a pretty sound blockade.
56... Nd7 57. Qd8 Qd6+ 58. Kg1 c3 59. Kh1
59. Qxh4? c2  )
59... Qd5
59... c2 Does not work because the knight on d7 is en prise at the end of the variation.
60. Nxc2 Qd1+ 61. Kh2 Qxc2 62. Qxd7 Qxf2 63. Qd4+ with an easy draw.  )
60. Kg1 Qb7 61. Qe7 Kg8 62. Qe8+ Nf8 63. Qa4 Qb1+ 64. Kh2 Qe1 65. Qc6 Qd2
65... Qxf2 66. Qxc3 Is similar to what happened in the game, except Caruana had his knight on h7. It is a negligible difference and Black no longer seems to have a significant advantage.  )
66. Kg1 Nh7 67. Qc8+ Kg7 68. Qc7 Qe1+ 69. Kh2 Qxf2 70. Qxc3 Kh6 71. Nc6 Qg3+ 72. Kh1 Qc7 73. Qc5 Qc8
73... f5 Would have preserved the illusion that Black has winning chances.  )
74. Qd6 Qf5 75. Ne5 Kg7 76. Qd4 f6?? This has to be in contention for blunder of the year. Akobian was already out of danger and now is the recipient of a free point.
77. Qa7+ Unfortunately for Caruana the king has good place to run.
77... Kh6 78. Ng4+ This has to be what Caruana missed. He likely assumed that
78. Nf7+ was the natural knight check. Even here, after
78... Kh5 the position is dead equal.  )
78... Kg5 79. Qxh7 Down a knight and about to have his pawns picked off, a flummoxed Caruana resigned.

While all the drama was unfolding, Gata Kamsky and Sam Shankland played a relatively uneventful draw in a Berlin Defense. Ray Robson, a student at powerhouse Webster University, could not shake Zherebukh, his collegiate rival from Saint Louis University. Despite a promising ending, Robson could not find a finishing touch and split the point.

Daniel Naroditsky, the third collegian in the field, was incredibly emotive throughout his game against Alexander Shabalov. Naroditsky, a junior at Stanford University, was visibly frustrated that he was unable to convert a winning position and found himself nearly lost. He ended up drawing, ending his losing streak at two games.

The Women’s Championship had three decisive results as well, but by comparison it was a quiet day. Tournament leaders Paikidze and Foisor drew without painstaking effort. That suited Foisor, who had the Black pieces. She will now face Zatonskih in Round 10.

Nazi Paikidze vs. Sabina-Francesca Foisor
US Championship (Women) | Saint Louis USA | Round 9 | 07 Apr 2017 | ECO: E04 | 1/2-1/2
1. d4 d5 2. c4 e6 3. Nf3 Nf6 4. g3 dxc4 5. Bg2 a6 6. O-O Nc6 7. e3 Bd7 8. Qe2 Bd6 9. Qxc4 O-O 10. Qe2 Qe7 11. Nc3 Rad8 12. Nd2 e5 13. d5 Na7 14. a4 c6 15. e4 Nc8 16. Nc4 Bc5 17. Ne3 Nd6 18. dxc6 Bxc6 19. Ned5 Nxd5 20. exd5 Bd7 21. Be3 Bxe3 22. Qxe3 Nc4 23. Qe2 Rc8 24. d6 Nxd6 25. Nd5 Qe6 26. Rfe1 e4 27. Nb6 Rcd8 28. Nxd7 Rxd7 29. Bxe4 Nxe4 30. Qxe4 Qxe4

Zatonskih pulled within a half point of the lead by beating Feng, who played an overly ambitious variation of the typically tranquil Queen’s Gambit Accepted and was down a pawn 16 moves into the game. Feng, who is competing in her first U.S. Women’s Championship, showed her youth by making a number of unforced errors. Zatonskih had little trouble finishing her off.

Anna Zatonskih vs. Maggie Feng
US Championship (Women) | Saint Louis USA | Round 9 | 07 Apr 2017 | ECO: D20 | 1-0
1. d4 d5 2. c4 dxc4 3. e4 c5 4. d5 Nf6 5. Nc3 b5 6. Bf4 Qa5 7. a4 Nxe4 8. Ne2 Nd6 9. axb5 Qb6 10. Ng3 Nd7 11. Bxd6 Qxd6 12. Bxc4 g6
12... Nb6 13. Qe2 f5!? Was a fascinating way to stop White from placing a knight on e4 and dislodging the queen on d6.  )
13. Nge4 Now Zatonskih is much better. Feng's queen gets kicked around, which costs her a pawn.
13... Qe5 14. O-O Bg7
14... Nb6 Again was the necessary move. Feng is worse, but she has the two bishops. Importantly, without the knight's in the way, the queen protects e7 from c7.
15. Ba2 Bg7 16. Re1 O-O 17. Nxc5 Qc7 is a battle.  )
15. Re1 O-O 16. Nxc5 Qd6
16... Qc7 17. Nxd7 Bxd7 18. Rxe7 Be5 Would give Black compensation for the two pawns, except that
19. d6! Is a crushing shot.
19... Bxd6 20. Bxf7+ Rxf7 21. Rxf7 Kxf7 22. Qd5+ Is White's point: the rook on a8 is lost.  )
17. N3e4 Qb6 18. Nxd7 Bxd7 19. Ra6 Qd4 20. b3 Though the position is not good, Feng is not yet totally lost.
20... Rfb8
20... Qxd1 21. Rxd1 Bf5 Was probably a better attempt. Zatonskih is up a pawn so she has nothing to worry about, but this move makes d5-d6 more difficult to play.  )
21. Qxd4 Bxd4 22. d6 e6
22... exd6 23. Rxd6 Wins a bishop.  )
23. Rd1 Bg7 24. Rc6! This is an extremely classy move. Black's counterplay is completely quashed.
24... Rb6
24... Bxc6 25. bxc6 Is hopeless. The passed pawns will win quite a lot of material.  )
25. Rc7 Rd8 26. Nc5 Bxb5 27. Nb7 Rf8 28. d7 Bf6 29. d8=Q Bxd8 30. Nxd8 Bxc4 31. bxc4 a5 32. c5 Ra6 33. Rdd7 a4 34. Nxf7 Rb8 35. Nh6+ Kf8 36. h3 a3 37. Rxh7 Ke8 38. Rh8#

Emily Nguyen suffered her eighth straight loss, this time to Tatev Abrahamyan. Abrahamyan’s reward is a clash with Paikidze, whom she can catch with a win. Jennifer Yu and Katerina Nemcova traded just one bishop and agreed to a draw after 43 moves. Meanwhile, Apurva Virkud proved that not all opposite-colored bishop endings are drawn in her win over Anna Sharevich.

Krush has won seven championships, but an eighth might elude her after she could not defeat Yip. Krush, who had Black, switched from the Caro Kann Defense, which she used against Abrahamyan and Zatonskih, to the Sicilian. After a balanced opening the momentum swung to Krush, who essayed a beautiful queen sacrifice. Yip had no choice but to return the queen and attempt to hold a draw in a pawn-down knight endgame. Yip smartly captured Krush’s a-pawn and used her own as a decoy to activate her king and take all of Krush’s remaining pawns.

Carissa Shiwen Yip vs. Irina Krush
US Championship (Women) | Saint Louis USA | Round 9 | 07 Apr 2017 | ECO: B48 | 1/2-1/2
Qxd6 35. Ng4 Yip must not have seen the bombshell coming.
35... Qxa3! An awesome tactic that is impossible to turn down once you see it, but perhaps there were better ways for Krush to have maintained the initiative. This position is very difficult to defend for White.
35... Qc5 It's a struggle to even come up with suggestions for White. Black, on the other hand, has many threats including a well-timed Rb4-b3.  )
36. bxa3 Rxc3+
36... Nxc3 37. Rd8+ And White should win easily.  )
37. Rc2 Forced. All other moved lost quickly.
37. Kb2 Rb3+ 38. Ka2 Nc3+ 39. Ka1 Rb1#  )
37. Kb1 Rb3+ 38. Rb2 Nc3+ Wins the queen back, with interest.  )
37. Kd1 Rc1#  )
37... Rxc2+ 38. Qxc2 Rxc2+ 39. Kxc2 f5 During the round Yasser Seirawan was quite critical of this move, stating that Krush could make this push at any moment. While I do not disagree with Seirawan, it is hard to come up with an alternate plan.
40. Ne5 g5 41. Nd3
41. fxg5 hxg5 42. Kd3 Would have allowed Yip to run her king to the center. Now the problem for Yip is that now Krush has a clear path to a passed pawn. These endgames are closer to a draw than they are to a win in most instances.  )
41... gxf4 42. gxf4 Kf7 43. Kd2 Ke7 44. Nb2 Yip had no other moves. Her king was cut off by Krush's knight, so it was time to go after the a4 pawn.
44... Nxf4
44... Nb6 45. Kc3 Kd6 46. Kd4 Is hardly a winning attempt.  )
45. Nxa4 Kd6 46. Nb2 Kc5 47. a4 Nd5
47... e5 48. a5 Kb5 49. a6 Kxa6 50. Nc4 Ng6 51. Nd6 Is a similar path to a draw. The a-pawn is merely a distraction that allows Yip to go after Krush's pawns.  )
48. Nd3+ Kc4 49. Ne5+ Kd4 50. Nc6+ Kc5 51. Ne5 h5 52. Nd3+ Kc4 53. Ne5+ Kc5 54. Nd3+ Kd6 55. a5 Kc6 56. Ke2 Kb5 57. a6 Kb6 58. Kf3 Nc7 59. Kf4 Nxa6 60. Ke5 Nc5 61. Nf4 Kc6 62. Nxh5 Kd7 63. Nf4 Ke7 64. Nxe6 Nxe6 65. Kxf5 Krush is sure to be disappointed, but Yip earned her half point.

With just two rounds to go, three players in the open section and four in the women’s division have a realistic shot of winning the title. All eyes will be on the Round 10 matchups of the top contenders, particularly the match up between Foisor and Zatonskih. Can Akobian handle Robson, against whom he has a phenomenal record? Will So topple Kamsky as he did a year ago? These questions and more will be answered Saturday in Saint Louis!

—————————————————————

Robert Hess is a former United States Junior Champion, recipient of the 2010 Samford Award (the most prestigious in the United States for young players) and was runner-up in the 2009 United States Championships. A 2015 graduate of Yale University, he is the chief operating officer of The Sports Quotient, a statistically-based sports site that he co-founded. He can be found on Twitter at @GM_Hess.