19...Rh6 20.Kf1 Rg6 21.Qf2 Qd7 22.bxc6 bxc6
23.Rg1
Nothing better, for Black threatens to win the Queen by 24...Bg3, after 23...Bxh3+.
23...Bxh3+ 24.Ke1 Ng4 25.Bxg4
If 25.Qh4 Nxe3 26.Rxg6 fxg6 27.Qg5 Ng2+ (better than 27...Nc2+) 28.Kd1 Nf4 and preserves three passed pawns with an extra pawn in the center for the piece.
25...Bxg4 26.Ne2 Qe7 27.Nf4 Rh6
27...Rf6 looks stronger, but, we believe, on examination it will not be found as sure as the move in the text, for although Black might have thereby won the Exchange and an additional pawn, his game afterward will not appear very satisfactory and seems to leave to the opponent a good attack with some chances of drawing and even winning, e.g. 28.Rxg4 hxg4 29.Qh4 Bxf4 30.exf4 Rxf4 31.Qh8+ Qf8 32.Qh5 (threatening 33.Qe5+) 32...Kd7 33.Qg5 Rf6 34.Nf1, followed by 35.Ne3, with a good game.
28.Bc3 g5 29.Ne2 Rf6 30.Qg2 Rf3 31.Nf1
Obviously his best, for he could not defend the pawn otherwise, and if 31.Nxf3 he would lose a piece by the answer 31...exf3.
31...Rb8
31...Bh3 seems good enough, but, we believe, Black's winning could at least have been made very difficult and much delayed if White had then elected to sacrifice his extra piece, e.g. 32.Qxg5 Rxf1+ 33.Kd2 Qxg5 34.Rxg5 Rxa1 35.Bxa1 Ke7 36.Rxh5, with a defensible game.
32.Kd2 f5 33.a5
Rather weak; but it is difficult to suggest a good move. 33.Nh2 might have led to the following variation: 33...Rh3 34.Nxg4 hxg4 35.Rh1 Qh7 36.Rag1 Kf7 37.Rxh3 gxh3, and if 38.Qxg5 then follows 38...h2 and 39...Rg8, winning the Queen.
33...f4 34.Rh1 Qf7
The decisive preparation in support of the Rook before opening the f-file.
35.Re1 fxe3+ 36.Nxe3 Rf2
Quite good enough and perhaps leading to a speedier decision than the tempting 36...Rxe3 37.Kxe3 Bf4+ 38.Kf2 (best) Rb3 39.Rhf1 Bxe2 40.Rxe2 Rxc3 41.Kg1, and if Black plays 41...Rg3 White would answer 42.Qxg3.
37.Qxf2
The sacrifice of the Queen was forced on this move; if 37.Qg1 Qf3 38.Nxg4 Bf4+ 39.Kd1 followed by 39...Qd3+ and mates next move.
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