Explanation

Clearance is similar to a discovered attack or discovered check, in that you move one piece to reveal a threat of another piece. For a discovered attack or check that threat is a direct attack or check. For clearance, that threat can be checkmate, or some other tactics.

A clearing move can be especially strong if it is a forcing move, for example a capture, a check, or an attack. In that case, the opponent often cannot handle that forcing move, and the revealed threat at the same time.

In this level the revealed threat is the promotion of a pawn. You move one piece out of the way of your pawn, so the pawn can promote on a subsequent move.

Examples

White can win with move 1...Kf7!, clearing the promotion square for the pawn and attacking the rook at the same time. The rook is in such an unfortunate position that it cannot prevent the promotion, because the king covers the g6 and e8 squares. White will have queen against rook, which is a winning endgame.

Sometimes the clearing move can be a sacrifice:

In this rook endgame, Black has a passed pawn on the 7th rank, which is blocked by their own rook. Simply moving that rook for example with 1...Rg1 would allow both players to get a queen after 2.a8=Q h1=Q. Instead, Black can win with the clearance sacrifice 1...Ra1+! 2.Kxa1 h1=Q+ promoting with check and controlling a8 with the new queen as well.

Here is a more difficult example:

Black has two rooks for a queen, and the a pawn is one square away from promotion. There are seven ways to move the rook and clear the promotion square. However, White is threatening a perpetual check with the queen on the 6th rank. Only 1...Rg1! prevents the perpetual check, for example 2.Qe6+ Kh8 3.Qf6+ Rg7. If White captures the rook, Black can promote with check, for example 2.Kxg1 a1=Q+ 3.Kg2 Qa7 and the queen can help to defend against checks.

Related motifs

You can also combine clearance with other motifs: