Abdel Irada: <<•>File it under g(oodbye)<•>>With all the heavy pieces on the g-file, intuition tells us Black will break through there somehow, and then deliver the coup de grâce by means of a threat incorporating mate on it and the h-file. It's just a matter of how to begin.
<<•> 32. ...Bxh3! >
White must either recapture or take the rook on g3; anything else merely allows Black to take a critical defensive pawn for nothing.
< (1) 33. Bxh3, Ng4†
34. Bxg4 ... >
Not to be countenanced is (a) 34. Kh1?, Rxh3† 35. Kg1/g2, Nf2†! 36. Kxf2, Qg2#.
< 34. ...Qxg4 >
Black threatens 35. ...Qh3#, forcing White's next.
<35. Bxg3, Qxg3†
36. Kh1, Qh3†
37. Qh2, Qxf1†
38. Qg1, Qxg1# >
So much for taking the bishop. How about the rook?
<<•> (2) 33. Bxg3, Qxg3† >
White has two retreat squares.
<<•> (2.1) 34. Kg1, Ng4 >
Black threatens mate with 34. ...Qh2. Some rook move is necessary to give the king room to run.
< (2.1.1) 35. Rf2, Qh2†
36. Kf1, Qh1†
37. Ke2, Bxg2
>
Black already has two pieces and an advanced passed pawn for a rook, and will soon win the exchange, leaving him over a piece to the good.
< (2.1.2) 35. Rf3, Qh2†
36. Kf1, Qh1†
37. Ke2, Qxg2†
38. Kd1/d3, Qxf3
>
Black is two pieces ahead.
<<•> (2.1.3) 35. Rfb1, Qh2†36. Kf1, Qh1†
37. Ke2, Qxg2†
>
This may be relatively best for White, but Black again has two pieces and an advanced passed pawn for a rook, and White's king is not yet safe.
If not one retreat, what of the other?
< (2.2) 34. Kh1, Ng4 >
To avoid mate on h2, White must move the bishop.
< (2.2.1) 35. Bxh3?, Qxh3†
36. Kg1 ... >
No better is (a) 36. Qh2, Nxf2 37. Rxf2 (else the knight discovers mate), Qxf1#.
< 36. ...Nxe3†
37. Kf2, Qxf1†
38. Kxe3, Rg3†
39. Kd4, Qc4# >
Perhaps another bishop move?
< (2.2.2) 35. Bf3, Bxf1
>
Black is a piece up and the attack lives on. And since 35. Be4 and 35. Bxd5 are no more promising, White must confess himself out of options.