The mating idea for Black is concealed here; the clue that enables you to unravel the position is the rook on g8—not because it necessarily will help administer mate, but because it gives you a natural way to open the White king’s pawn cover. If you have a way to take out the g2 pawn, as Black does here, it calls for experimentation to see what patterns might result. The thinking starts 1. …Rxg2+. Since the rook then has protection from the bishop on b7, it wouldn’t even be a sacrifice; White would be forced to reply Kh1. Now Black has the kernel of a discovered check on the long diagonal. He could use it to go after White’s queen with his rook, but focus on mate. Withdrawing the rook to g6 almost creates Morphy’s mate, but not quite: White interposes his bishop on e4 and Black’s threat is extinguished.

So the better route now is for Black to consider his other resources and how he might involve them. He has two bishops aimed into the White king’s corner and a knight available as well—signals that Blackburne’s mate or some other bishop-driven pattern may be possible. If Black could get his knight to g4 then both bishops would have open lines; and if the White king could be brought to h2, then Black could move his knight to g4 not only with a discovered check but with double check. So Black plays the ingenious 2. …Rh2++. If White moves his king to g1, Black mates immediately with Rh1: a heavy piece in the corner supported by a bishop. So White is forced to play KxR. We arrive at the position in the next frame.