Chess Board
[ECO code C33]
(KGA:) Bryan C.G. - "Immortal Game" Var.
Both of White's rooks were under threat of capture but his KB4(f4) bishop to Q6(d6) turned the game.
18..BxB: If Black's Bishop on QB4(c5) removes the White bishop on Q3(d6) (diagram) then White wins by exchanging bishops (for check) before forcing the KB-file open for a queen mate on KB8(f8). B-Alt.
     White  Black	Continue:
 18. B-Q6!! BxB     19.	KtxB ch K-Q1
		    20.	KtxP ch K-K1 fcd
		    21.	Kt-Q6 ch K-Q1
		    22.	Q-B8 mate
Example ends: Undo or Jump or Clear