Position after move 24.
PGN: 1.e4 c5 2.Nf3 d6 3.Bc4 e6 4.d4 cxd4 5.Qxd4 Bd7 6.O-O Nc6 7.Qc3 Nf6
8.Nbd2 Rac8 9.e5 dxe5 10.Nxe5 Nxe5 11.Qxe5 Bc6 12.Bd3 Bd6
13.Qg5 O-O 14.Nc4 Be7 15.Qf4 Qd5 16.Ne3 Qh5 17.f3 Rfd8
18.g4 Qh3 19.Qg3 Qxg3+ 20.hxg3 Bc5 21.Kh2 Rd7 22.a4! e5
23.Bf5! e4 24.fxe4 [0-1]
>>> The threat is now - e5, combined with the pin on the rooks.
This puts black in a zugwang.
If black continues bxn, bxb, then he is forced into nxe4 (to
prevent e5) and white can continue either r-f4, or c4, and
black will loose the exchange and be facing a lost end game.
The position has interesting balance - the key is finding the
right move sequences. If white plays b x r immediately then
he looses, because blacks rook will give check on c2.