Abdel Irada: <Rounding up the usual suspect<<<>>>>
I have spoken here before of "intuition born of experience." When one sees a position of this kind, in which a crucial pawn is defended only by a king, and numerous hostile pieces are bearing down on its vicinity, a sacrifice comes immediately to mind. And when that square is f7 or f2 (statistically the squares more sacrificed on than any others), it might as well sport a billboard reading "SACRIFICE HERE."
Therefore we begin:
White must make a decision: to accept the sacrifice or decline it and look for something else to do. In this case, the sac isn't forcing; there are no immediate threats, and White is free to ignore it if he chooses. On the other hand, unless he can find a way to win back a pawn, he will be left a pawn down and with a further weakened king's field.
As it happens, there's only one target for White: the pawn on c5. So, as a practical matter, White can either take this pawn or accept the sacrifice and see if he can refute it. Any other choice is too passive.
Let us, then, examine these choices respectively.
<(1) 27. Qxc5, Qxc5
Here, Black would like to take advantage of the "pinned" e-pawn with ...Nd3, forking the rooks. Unfortunately, the pawn isn't really pinned because the rook on e1 is defended. So, what if we remove the guard?
This presents White with what <Once> would call a "GOOT": "Get Out Of That!" If he takes on f3 with the pawn, the rook on e1 falls with check; if with the bishop, 29. ...Nd3 wins the exchange.
But what if White takes the knight?
Now, if Black plays the obvious 29. ...Bxg2, White's choice looks good: He will recapture on g2 with complete equality. However, Black has a stronger choice.
30. Kg1, d3
31. Rd5, Rd8 >
And suddenly the passed pawn looms as an implacable menace. White is only a pawn down ... but what a pawn!
Now, let's see what happens if White takes up the gauntlet.
<(2) 27. Kxf2, Qe3
28. Kf1, Bxf3
White can also take with the bishop, but this makes no difference, for it will only transpose.
30. Bxf3, Qxf3
31. Kg1, Qxg3<>>
Another move, another decision. Should the king run towards the wing or the center?
We will consider these options in order.
<(2.1) 32. Kh1...<>>
This is the safer course because no obvious mating attack ensues. But this does not mean it is *safe*; one can lose without being mated. Nonetheless, I will consider it the main line because it offers White his best practical chances.
33. Rxe1, Qxe1
34. Kg2, Qxh4
35. Qxc5, Qe4
36. Kf2, d3 <>>
Thanks to Black's queen position, White has only one check, so perpetuals aren't possible as long as Black remains cautious. Meanwhile, Black is three clear pawns ahead, and the passed d-pawn is once again very dangerous.
Having seen that White can't genuinely "survive" running to h1, we now test the idea of moving toward the center and trying to hold.
<(2.2) 32. Kf1?!, Rf8
33. Ke2, Rf2
34. Kd1, Qf3
35. Re2, d3 >
Not so coincidentally, this pawn advance is once again White's undoing. In this case, it wins a pinned rook. And after the forced 36. Rc2, dxe2; 37. Rxe2, Rxe2; 38. Qxe2, Qxe2; 39. Kxe2, g5, Black's two extra pawns win easily.