Cover up the moves in the game below and look at the diagrammed position. Amos Burn, one of the world's best players toward the end of the 19th century, playing Black, looks to be dead lost. White will regain his sacrificed piece and mate Black in short order, right? In this seemingly hopeless position, Burn found what I consider the most astounding move in chess history. (To clarify, I mean astounding good moves. No doubt there are lots of astounding bad moves - say, where White could have mated in one and instead played a move that allowed Black to mate White in one.) Do you see it?
Chess problemists will tell you that Burn's move 33 is an extremely rare example of the Novotny theme in actual play. That is, 33...Qg4!!! moves the queen to the square that is the intersection of the d1-h5 diagonal controlled by White's bishop, and the g-file, controlled by White's rook. If the rook captures the queen, it blocks the bishop, allowing 34...Nf3+ and 35...Nxd2. If the bishop captures the queen, it blocks the rook, allowing 34...Bxd2. There are two other plausible continuations: 33.hxg4? allows Black to win the queen either way, leaving him with an extra piece, and 33.Qxg5+? Qxg5 34.Rxg5+ Kh6 wins a piece for Black. Note that (as Burn pointed out) 33.Be4! would have deprived him of this resource, winning easily for White.