Pillsbury’s Mate is a rook and bishop checkmate pattern where the bishop controls the corner square next to a castled king. For this to happen, the pawn shield in front of the king must be compromised.
Pillsbury’s Mate Example 1
Diagram above: 1.Rg1 demonstrates Pillsbury’s mate. The main feature of this pattern is the role of white’s bishop that covers the escape-square, h8.
Pillsbury’s Mate Example 2
The second example is from the game Savic vs. Radojevic Montenegro Team Championship 2006. I found this game on the chessonly.com website.
Diagram above: White plays 1.Bxe6! But can’t black just grab the black queen?
The next diagram shows what happens if black captures the white queen, 1… Qxd2:
Diagram above: White will now execute Pillsbury’s Mate, 2.Bg7+ and black is forced to play 2… Kg8.
Diagram above: 3.Bf6+ (or Be5+) is a discovered check by the white rook on g1. Then, after the forced move 3… Qg5, 4.Rxg5# is checkmate.
Interesting Notes on Pillsbury’s Mate
You can find a complete annotated game on chess.com, supposedly between Harry Pillsbury and Francis Lee, played in London 1899. However, in a good article by chess historian James Stripes, he writes that there seems to be a number of contradictory facts in published media with regard to some of Pillsbury’s games.