Step 1 · The piece behind
White to move
5r2/pp3pkp/2q5/8/3N4/8/PB3PPP/6K1 w - - 0 1Your bishop on b2 points at the king on g7, but your knight on d4 stands in the way.
What happens when the knight moves?
Quick check
- The bishop gives check
- Nothing — the bishop is too far away
- The knight is lost
Show the correct answer
Correct answer: The bishop gives check — Yes — a discovered check. The knight can go anywhere it likes, even take the queen, and Black must answer the bishop first.
- Nothing — the bishop is too far away — Distance does not matter to a bishop. With d4 empty, the diagonal from b2 runs clean through to g7.
- The knight is lost — No black piece can reach d4 right now. And once it moves, Black has a bigger problem: check.
Step 2 · Move it with a purpose
White to move
5r2/pp3pkp/2q5/8/3N4/8/PB3PPP/6K1 w - - 0 1Move the knight so that it takes the queen — the bishop gives check at the same time.
The move: Nd4xc6
Knight takes queen, with check from the bishop. Black has to deal with the check before anything else.
Common mistake: The queen on c6 is still there. Knight takes c6 — and the bishop on b2 gives check as the knight moves.
Black answers the check
Black to move
5r2/pp3pkp/2N5/8/8/8/PB3PPP/6K1 b - - 0 1Black steps out of check. Now the pawn on b7 attacks your knight on c6 — save it.
Step 3 · Keep the knight
White to move
5rk1/pp3p1p/2N5/8/8/8/PB3PPP/6K1 w - - 1 2The knight is attacked by the pawn on b7. Move it to a square no black piece attacks.
The move: Nc6-e5
Safe — and you are a whole queen up.
Common mistake: The knight can still be captured. Put it where no black piece attacks it — e5 or e7, for example.
What you learned
When one of your pieces stands in front of another, moving it can attack twice: once with the piece that moves and once with the piece behind it.
Practise this idea
Public-domain positions that turn on exactly what this lesson taught.
- Discovered attacks — 12 positions