|KEG: Post IV
After 30...Qc8, Mason seemed to be close to victory. But there was excitement yet to come, as Sterling pressed forward relentlessly in his wild attacking efforts.
31. Re2 Qxg4
Mason is now two pawns up. But Sterling is playing for mate.
32. Rg2 Qf5
32...Qd7 was better, but Mason still has the game in hand.
33. Qc2 is "better," but Sterling wants to play on the g-file.
Not bad, but 33...Rc4! would have shut down Sterling's hopes. If then 34. Rxg7 RxB!
Still focused on the g-file, but allowing a nasty response by Mason. Best--though probably hopeless--was 34. Qc2.
Contrary to what Rosenthal claims in the Tournament Book, 34...Nxf4 was best. Rosenthal claims that White would then obtain a defensible game with 35. Rf2 (actually, 35. Qg4 was "best" for White here), but he only considers 35...g5 and ignores Black's best move: 35...Qe4+ which is crushing. Even after Rosenthal's inferior 35...g5, Black still has a clear win in this line. After Rosenthal's supposed equalizing move: 36. b4 (36. BxN is best) Black wins with 36...Qd5+.
Even after Mason's inferior 34...Re4, he still should win easily.
35. Qg4 was "best," but it is too late for Sterling to back off from his madcap attack.
Good enough, but Mason should have begun exploiting his Queen-side majority with 35...c5
36. b4 is probably "best," but Sterling is not interested in what is happening on the Queen-side.
More than sufficient, but bringing his Knight to the attack beginning with 36...Ne7 was best.
37. Qg3 was "best," but Sterling--as will be seen--is planning to set a trap for Mason.
Mason could have ignored Sterling's "threats" with 37...Rge8!
Here it is! Sterling ignores the theoretically better 38. Qf3 to set a little trap for Mason.
Here was the position after 38. h5?!
click for larger view
This move is fine, but as Rosenthal pointed out in the Tournament Book, Mason could have simply played 38...Qxh5.
Sterling's hope is that Mason would play 38...Qxh5 39. Rh4 Qf7??? after which had would have had a mate in three beginning with 40. Rxh7+!!. But Mason after 38...Qxh5 39. Rh4 could simply have played 39...Qf5! ending Sterling's hopes.
In fairness to Mason, his move---though less immediately decisive than 38...Qxh5--still wins.
39. R4g2 Rge8
40. Qg3 was somewhat better, but the game is over.
Mason should have started a Queen-side march with 40...c5, but the text also does the trick.
Allowing Mason to swap Queens. The move is therefore equivalent to resignation. Sterliong should probably have played 41. Qg4, but that would also have allowed a Queen trade.
41...Qxh5+ was of course best, but it is easy to sympathize with Mason's desire to get the Queens off the board and ending Sterling's clumsy mating threats.
42. RxQ Re1
If 43. Rxg7 RxB!
44. Rg1 RxR+
45. KxR Kg8
Mason is now two pawns up in a Knight versus Bishop ending and the game is over.
The remaining moves are of no interest.
46. Kf2 Kf7
47. Kf3 Ke6
48. Kg4 c5
49. f5+ Ke5
50. h6 gxh6
51. Bxh6 Ke4
52. Bf8 c4
53. Bc5 a5