Why should I learn it?
Because it’s quite useful for pawn-race type positions. If you know how to win this type of position, you’ll earn many extra half-points in your games.
When do I use it?
Usually the way this plays out is when you promote before your opponent, but his pawn is almost reaching the eighth. Now, if he has a Bishop-file pawn, usually he can draw by a clever maneuver where his King reaches the Rook square and you cannot take the pawn lest you stalemate. But in the cases where your King is close enough, you can actually checkmate him easily.
Link to Practice Problems
Step-by-Step Guide on Queen vs pawn
It is White to move. In this position, White would be able to force a mate in two by only moving the queen.
- Qg4
This limits Black’s next move to only Ke1, thus forcing the mate next.
(1. Kd2?? is stalemate.)
(1. Kd3 also wins, although with more moves. 1. …Ke1 2. Qe3+ Kf1 3. Qg5! Ke1 4. Qc1#)
- …Ke1
Forced.
As you can see here, Black’s king now only has f1 to retreat to. What would be the move that takes away all the squares from the Black king?
- Qd1#
Checkmate.
By properly limiting Black’s options, White was able to bring the enemy king into the killing zone and go for the mate.