The razor's edge

This is the position after 33...hxg4 in Forecookies - Verns2 in a team game against The Wings of Hope.  Phil has played a positionally sound system against a Sicilian, but black has broken through on the Queenside with the threat of the passed, connected b & c pawns.  Black is so eager to break things open that he plays hxg4 and allows the Knight fork: 34.Ne6+ which Phil takes.  After the natural 34...Kd6 35.Nxf8 gxh3+ Phil realizes that the pawn recapture may be poisoned, which may in fact be black's idea behind allowing the fork and loss of the exchange.  If white plays 36.Kxh3 (position below), for example:

Black seems to have a very strong attack.  One reasonable possibility is that the game continues: 36...Rxf8 37.Rxb4 Qh7+ 38.Kg2 g4 39.fxg4 Qe4+ 40.Kg3 Rg8 41.Rf6+ Kd7 42.Rf7+ Kc8 43.Rb7 (desperate) Rxg4+ and white loses.

White may well have better resources than I have found so far [if you find a winning line for white after 36.Kxh3, let us know!], but it is clear that Phil foresaw risks with 36.Kxh3... and decided that he would give up the pawn and try to consolidate his position up the exchange (rook for knight).  Why allow all this counterplay?  So Phil plays the apparently safer 36.Kh2 tucking in behind the pawn instead.
 Black now has to prove his exchange sacrifice works even against a positionally sophisticated player who doesn't just jump at pawn captures!  Under pressure, the Latvian continues 36...Rxf8 37.Rxb4 Kc5 38.Rb7... and black faces a critical position:

Black's exchange sacrifice idea required that he blast open the pawns around the white King, so he must have considered 38...g4-- and his position would have been strong had he followed through with his original strategic plan: 39.Rc7+ [39.fxg4 Nxg4+ is a disaster for white] Kd6 40.Rc6+ (giving back the sacrifice, trying to survive) Nxc6 41.dxc6 Kxc6 42.Rg1 and white doesn't find a way out.  Is there a much better defense for white?  It appears that 38...g4 was both strategically coherent and correct, while black's actual play, 38...Qd6, was weaker, and the product of his nerves faltering in the face of Phil's psychologically-savvy and positionally interesting 36.Kh2. 

Black's attack is still active, however, so white has to continue to defend ferociously. The game continued with 39.f4 gxf4 40.Rg7 f3 (ominous!) 41.Qd2 Nd3 (revealed) + 42.Kh1 ... and once again black falters. Here is the position:
:
At this critical moment, black has the counterintuitive offer of a Queen exchange, which many defending players would embrace gladly, but after 42...Qf4 43.Qxf4 Rxf4 44.Rd7 f2 45.d6 Rd4 46.Kh2 Rxd6 47.Rc7+ Rc6 black is clearly much better.  Even if white sees this and plays much more aggressively with 43.Qa5+ Kd4 44.Qxa6 Kc3 45.Qa5+ Kc2 46.Qc7 Kd2 and now white trades the Ladies: 47.Qxf4 Rxf4 48.Kh2 f2, black is still winning.

Instead, in this complex position, black instead plays 42...f2 and Phil responds with the incisive 43.Qe3+!


Following the incisive 43.Qe3+!

 I think this move is deeply insightful.  Black has been faltering very slightly, not entirely sure of himself in his attacks, not demonstrating long term consistency with his apparent plans -- and Phil has forced black to make a complex strategic decision which requires just those talents Verns2 has not demonstrated.  What should black do here?  He has 43...Kb4!! which can draw if white wants one: 44.Qd2+ Kc5 45.Qe3+ etc.  Note that after 43...Kb4!! white doesn't really have anything better than a draw.   He has to deal with the advanced pawns, and if he tries the natural 44.Rh7 ... he is in for a terrible surprise! Black drives his Queen into White's bedroom with 44.Rh7 Qxd5+ 45.Qe4 Qxe4+ 46.Kh2 Qg2#.  So if black offers a draw here, white should take it.  All that said, Black has to be perfect to win or draw -- he can just as easily lose in this razor's edge position!

Instead of 43...Kb4, black tries the natural but deficient 43...Kxd5? and Phil pounces on his mistake!  44.Rg5+! Kc6 45.Qe4+ Kb6 46.a5+ Kc7 47.Rg7+ ... and now mate will soon be forced.  Black plays on
47...Kc8 48.Qb7+ and black doesn't hang around for the denouement: 48...Kd8 Qa8+ Qb8 49.Qxb8# and here it is Black's Queen instead of White's who must throw herself in front of a mate-threatening Queen.

What a battle!  Phil scores another point for The King Stompers.  Well done.