(1) Yu,Yangyi (2697) - Robson,Ray (2628) [B97]
Millionaire Chess Semifinal Las Vegas, 2014
[GM Lubomir Kavalek/The Huffington Post]

1.e4 c5 2.Nf3 d6 3.d4 cxd4 4.Nxd4 Nf6 5.Nc3 a6 6.Bg5 e6 7.f4 h6 8.Bh4 Qb6 The postponed Poison Pawn variation of the Najdorf Sicilian.

Accepting the challenge is the most principled decision. [White does not have to sacrifice the pawn and can play 9.a3 Be7 (9...Qxb2? 10.Na4 wins.) 10.Bf2 with good play.]

9...Qxb2 10.Rb1 Qa3 11.e5 dxe5 12.fxe5 g5
A sharp variation, leading to playable game for black. [The second popular line is rather unbelievable: 12...Nfd7 13.Ne4 Qxa2 14.Rd1!? (14.Rb3 Qa1+ 15.Kf2 Qa4 is good for black.) 14...Qd5 15.Qe3 Qxe5 16.Be2 and despite being three pawns down, white pieces radiate a lot of energy.]

13.exf6 gxh4
Up to here, the line is rather forced.

14.Be2 Nd7 15.0-0 Qa5 16.Kh1 Qg5 17.Qe1
According to GM Lubomir Ftacnik, this move was tested three years ago 2,500 times in computer games, while humans ventured there only a few times. [The main choice in this position was 17.Rf4 e5 18.Nd5 exd4 19.Qxd4 with a good compensation for the piece.]

An improvement. [After the previously played 17...Bd6 18.Ne4 Qe5 19.Nxd6+ Qxd6 20.Qxh4 white has a big advantage.; The computers suggest 17...h3 18.gxh3 Qe5 19.Nf3 Qe3= ]

18.Nf3 Qc5
[Black wants to keep his queen active, but 18...Qg7 19.Nxh4 Be7 20.Bf3 0-0 is roughly equal.]

19.Na4 Qc7 20.Nb6 Rb8 21.Qxh4 Be7 22.Qd4
Trying to secure the square e5 for his knight.

22...Rg8 23.Ne5 Rg5 24.Ng4 Nxg4 25.Bxg4 f5?
A reckless move and white finds the refutation. [Black should have tried 25...Bc5 26.Qh8+ Bf8 (26...Ke7 27.Rxf7+ Kxf7 28.Qh7+ Rg7 29.Rf1++- ) 27.Bf3 Qe5 ]

Robson might have overlooked this sacrifice. White gets a strong pressure on th e-file.

[Or 26...Rxf5 27.Rxf5 exf5 28.Re1+- ]

27.Rbe1 Kf8 28.Qh8+
[This should win, but 28.Nd5 Qd6 29.Rxe7 was even better.]

28...Rg8 29.Qxh6+ Rg7 30.Nxc8 Qxc2
Suddenly, black is threatening a mate and Yu gets nervous. [But not 30...Rxc8 31.Rxf5+ Kg8 32.Qe6+ Kh8 33.Rh5+ Rh7 34.Rxh7+ Kxh7 35.Qf7+ Kh8 36.Rxe7+- ]

31.Qh8+ Rg8 32.Qh3
[White misses a winning tic-tac-toe combination: 32.Rxf5+! Qxf5 33.Qxg8+! Kxg8 34.Nxe7+ Kf7 35.Nxf5+- ]

32...Rxc8 33.Rxf5+ Ke8 34.Qh5+?
The last moment when white misses the win, but the combination is not easy to calculate for human players. The computers provide the answers: [34.Rxe7+! Kxe7 35.Qh7+ Kd6 36.Rf6+ Ke5 (36...Kd5 37.Qd7+ Kc5 38.Qe7+ Kb5 39.Qxb7+ Kc4 40.Rf4+ Kd3 41.Qd5+ Ke2 (41...Kc3 42.Qd4# ) 42.Qe5+ Kd1 43.Rf1+ Kd2 44.Rf2+ Kc1 45.Qa1+ Qb1 46.Rf1++- ) 37.Qe7+ Kd4 38.Rf4+ Kd3 (38...Kd5 39.Qd7+ Kc5 40.Qd4+ Kb5 41.Qb4+ Kc6 42.Rf6+ Kd5 43.Rd6+ Ke5 44.Qd4+ Kf5 45.Rf6+ Kg5 46.Qf4+ Kh5 47.Rh6# ) ; White also has 34.Rf2 , trying to deflect the queen, but it is not as strong. ]

White lost the thread and the black king is escaping.

The wrong check. White had to play [35.g3 ; or 35.Qf3 ]

35...Kc7 36.Qe5+ Kb6 37.Re2 Qb1+ 38.Re1 Qxa2! 39.Qe4 Qc2!
Robson played two precise queen moves and the flashy combination is easily twarthed.

40.Rb1+ Ka7 41.Rxb7+ Ka8!
The refutation. White is weak on the first rank and his pieces are hanging. [But not 41...Kxb7? 42.Rb5+ Kc7 43.Qxe7+ Kc6 44.Qb7+ Kd6 45.Rd5+ Ke6 46.Qd7+ Kf6 47.Qd6+ white wins.]

42.Qf3 Qxg2+!
The final mating combination.

43.Qxg2 Rc1+
[43...Rc1+ 44.Qg1 Rcxg1# ] 0-1