Explanation

Let’s raise the stakes by looking at luring the king into a checkmate with a piece sacrifice. As mentioned previously, a sacrificed piece that lures another piece to a square is called a decoy. The following diagrams illustrate the use of decoys leading to checkmate:

Sometimes a sacrifice is possible to remove other pieces that are shielding the king from attacks—for example, the pawns shielding the king after castling, as in the first diagram: White can sacrifice the queen with 1.Qxh7+! This removes the h-pawn, which was shielding the king from attacks on the h-file. The decoy forces Black’s reply 1...Kxh7, after which White can checkmate with 2.Rh5#.

In the second diagram, White can sacrifice the queen with 1.Qxg8+! to remove the rook g8, which was shielding the king from attacks on the back rank. The decoy forces Black’s reply, 1...Kxg8, and also clears the way for the rook, which can now checkmate with 2.Re8#.

In the third diagram, the decoy does not remove a piece shielding the king: 1.Rh8+! forces 1...Kxh8, so the king no longer defends f8. White can then checkmate with 2.Rf8#.

Examples

Sometimes a sacrifice is possible to remove other pieces that are shielding the king from attacks, for example the pawns shielding the king after castling.

White can sacrifice the queen with 1.Qxh7+!
This removes the pawn h7, which was shielding the king from attacks on the h-file.
The decoy forces Black's reply 1...Kxh7, after which White can checkmate with 2.Rh4#.

Here a young Alexander Alekhine sacrificed his queen with 1...Qxf1+!
This removed the rook f1, which was shielding the king from attacks on the back-rank.
The decoy forced White's reply 2.Kxf1, and also cleared the way for the rook, which could now checkmate with 2...Rd1#.

Sometimes a decoy can even work without capturing anything:

White can win with the decoy 1.Qh5+!
This forces the king to h5, and deflects it away from protecting h7.
After 1...Kxh5, White can checkmate with 2.Rh7#.

Related combinations

It is also possible to decoy a piece to a square where it can be attacked in a subsequent tactic.