Tactics: Good Move? Better Move?
Black has just played 23...Qf4, attacking the h4-pawn and not fearing h4-h5.
Question 1: what happens after 24. h5 gxh5?
Question 2: does White have anything better?
From M.Chang - O. Nikulich,
Pere Noel, Montreal (2013.12.26)
Answer 1: what happens after 24.h5 gxh5....
Spoiler: Highlight to view
The game continued 24. h5 24... gxh5
24...Nxh5 is weaker: 25.Nxh5+ gxh5 and White has a strong attack after either 26.Re3 or 26.Re5.
25. Qh7+!! (Spectacular, but also the only good move, as otherwise White has just given the h-pawn for free.)
25... Kf8??
It's hard to overestimate the power of surprise, but otherwise Black might have found the much better 25... Nxh7 when 26. Nxh5+ Kh8 27. Nxf4 Bd7 leaves White better, but it's a long way to a win.
26. Qh8+ Ke7 27. Nf5+
Winning, but once again 27. Rxe6+! is crushing: 27... fxe6 28. Nf5+ ! Kd7 29.Qg7+ only move Kc8 30.Qxf6 +-.
27... Kd7
27... Qxf5 is a good try, but the alert 28. Rxe6+! wins.
28. Qxf6
1-0
Scoring a nearly 300 point upset in: Michael Chang (1792) vs Oleksandr Nikulich (2085) Pere Noel, Montreal (2013.12.26).
Question 2: Does White have something better?
Hint:
Spoiler: Highlight to view
White does have something better: 24.Rxe6!... but you have to see the follow up on move 27.
Answer 2:
Spoiler: Highlight to view
24.Rxe6! Rxe6 25.Rxe6 fxe6 26.Qxg6+ Kf8 27.Bf5!! This the hard move to see in advance, but it's the only move that gives White any advantage.
I'll consider three moves for Black:
27... exf5
27... Ne4
27...Ng8
27... exf5 28.Qxf6+ Kg8 (28... Ke8 29.Qxc6+ +-) 29.Nxf5 Qc1+ 30.Kh2 Qf4+ 31. Kh3! there's no perpetual, and 31... Qc7 32.Ne7+ wins the Q, since the alternative is mate: 32...Kh7 33.Qg6+ Kh8 34.Qxh6#.
27... Ne4 28.Bxe4 dxe4 29.Nh5 Qf7 30.Qxh6+ Ke7 31.Qg5+ Kd6 32.Nf6 +- White wins at least another pawn and keeps a strong initiative against Black's exposed K.
27...Ng8 is probably Black's best, trying to curl up in a ball and hope to save a difficult Q ending: 28.Nh5! Qxd4
(28... Qxf5 leads to a worse version of the main line below, 29.Qg7+ Ke8 30.Qxg8+ Kd7 31.Qxa8+- White wins the a7 pawn and will be able to check his Queen into a good position before pushing the a-pawn.)
29.Bxe6 Ke7 30.Bxg8 Rxg8 31.Qxg8 Qd1+ I think White is winning, but Q endings are difficult, and although Black's K is exposed, his passed pawn (d5) is further advanced than White's on a2 will be.