The following is the so-called "Beauty Line" as written up by Paul Hodges, a professional chess writer. In all lines it mates faster than raw xhess engine output. In addition the chess engine line is known theiry having been worked out independently by both Vheron and Tarrash in the 1920's
White has nothing better than shuffling his rook along the back rank in view of Black's permanent back rank threat, so the exchange of rooks is inevitable. The sequence we will show is not absolutely forced but is meant to highlight the unavoidable winning plan for Black.
53...Ke2 54.Rg1 Rf2 55.Rh1 Rf1+ 56.Rxf1 Kxf1
STEP TWO: The Black king relocates to h5 to create a Zugzwang and to win a White kingside pawn.
As White's king has no moves, the only defensive try is to create a stalemate defense by advancing his a-pawn to a5 and then sacrificing his bishop.
57...Kg2 58.a5 Kf3 59.Be7
Now White is reduced to shuffling his bishop.
59.h5 gxh5 60.Be7 Kg4 61.Bd8 Bc4+ and Black releases the stalemate and White will be forced to give up his bishop for the passed Black pawn.
59...Kg4 60.Bd8 Kh5 61.Bg5 Bf5 (Diagram 4)
Non-SCO note: This is the position envisioned by the WT at Move 34.
62.Be3 Kxh4+ as Black will be able to release the stalemate and force White to sacrifice his bishop.
Pal Benko, Chess Life, August 2003:
If 62. Be3 then 62.
Kxh4 is the same. Black gets his pawn and after 63. Bd2 Kh5 64. Be3 Be6 followed by
g6-g5 he can get a second one as well.
STEP THREE: Black creates a passed pawn on the kingside.
63.Be7 Kh5 64.Bd8 h6 65.Be7 Kg4 66.Bd8 g5 67.hxg5
67.Bxg5 hxg5 68.h5 (68.hxg5 Kf4 69.g6 Ke3 70.g7 Bh7 71.g8Q Bxg8+) 68...Kf3 (68...Kxh5??= Stalemate) 69.h6 Ke4!+
Eventually White has to play this move so that he can attempt to control the advance of the Black h-pawn.
h4 69. g7 Bh7 70. Bc7 h3 71. Bd6 Kf3 72. g8=Q Bxg8 73. Kb1 Kg2 74. Kc1 h2 75. Bxh2 Kxh2
Black wins since he will eventually also take the a5-pawn. Note that without the a-pawns the position is a theoretical draw.
STEP FOUR: The Black king relocates to b5 to attack the White a-pawn while maintaining the imprisonment of the White king on a1.
69.Be7 Kf3 70.Bd8 Bc2
So Black can cross on the e4-square without releasing the White king.
71.Be7 Ke4 72.Bd8 Kd5 73.Bf6 Kc6 74.Be7 Kb5 75.Bd8 Bf5
STEP FIVE: Black wins the White a-pawn, and then advances his a-pawn to a4 and changes the guard on the White king's prison from his bishop to his king.
Or 76.Bc7 h4 77.Bg3 h3 78.Bc7 Be4+ etc.
76...Kxa5 77.Bd8+ Kb5 78.Be7
Or 78.Bc7 h4 79.Bd8 h3 80.Bc7 a5+ etc.
78...a5 79.Bd8 a4 80.Be7 Kc4 81.Bf6 Bc2
Keeping the door closed as the Black king passes over d3.
82.Bg5 Kd3 83.Be7 Kd2 84.Bg5+ Kd1 85.Be7 Bf5 86.Bf6 Kc2
STEP SIX: Black creates a winning passed pawn on the queenside to overload the White defenses.
Now Black will be unable to control a3 and h4.
88.Bd6 88.Bf6 a3 89.bxa3 h4 90.a4 (90.Bxh4 b2++) 90...h3 91.Be5 h2 92.Bxh2 b2++
88...h4 89.Be5 h3 90.Bd6 a3 91.Be5
91...h2 92.Bxh2 axb2 Mate
An aesthetic finish mating with Najdorfs Pawn (see 5
a6). In light of this overall winning plan (or some similar variant thereof prepared by Black), De Firmian resigned after 52...Rh2.