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TacticsPlay as white

Clearance and Interference

Lines decide tactics: open one of your own, or cut one of theirs.

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Introduction

Long-range pieces work along lines, so tactics are often about which lines are open. Clearance means getting your own piece out of the way of another; interference means putting something in the way of theirs. Both usually cost material — and both are worth it, because the line matters more than the piece.

Lesson Content

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The white queen on c1 wants the f4-square: from there she would attack the black king on f5, which has no flight squares left. The only thing in the way is White's own pawn on e3.

Clearance
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1. ..e4+

The pawn steps forward with check and clears the diagonal behind it. Black has nothing better than 1. ..dxe4, and now the c1-h6 diagonal is wide open — the queen comes down it and Qf4 is checkmate, with every escape square covered.

Clearance
Alternative Moves
Qd2 — Lining the queen up looks natural, but 1...g5 gives the black king air and the position is only a draw.
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2. Qf4#

Checkmate on the square the pawn vacated. The queen is defended by the pawn on g3, and every escape square is covered by White's own pawns.

ClearanceMating Net
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Now look down the d-file: White's rook on d1, the black rook on d7, and the empty back rank behind it. The black king on g8 has no luft. The rook on d7 is the only defender of d8 — and White has a second piece that can reach it. Get a white piece onto d8 and, with the king shut in by its own pawns, that is mate.

X-RayBack Rank
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3. Qd8+

The queen lands on d8 where the black rook can take it — but the white rook on d1 is looking straight through the black rook at that square. Black has to capture, and the recapture drags the rook onto d8, where Rxd8 is checkmate.

X-RaySacrifice
Alternative Moves
Rxd7 — Trading rooks first throws the whole idea away: after 1...Qxd7 the back rank is defended and the game is level.
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3. ..Rxd8#

Checkmate. The black rook was pulled onto d8, where the white rook simply takes it — and the king behind its own pawns has nowhere to go.

X-RayBack Rank
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Black's rooks on a8 and e8 defend each other along the eighth rank. Which check makes the black king step between them?

Interference
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Why are clearance and interference two sides of the same idea?

ClearanceInterference

Key Takeaways

  • Clearance: move your own piece out of the way, with a threat if you can.
  • Interference: block the line a defender is working along — the king can be the blocker.
  • An x-ray is a line that works through a piece: your rook still defends the square behind it.

Now play it through

Step through every move on a real board, try the wrong ones, and ask Knighty why they fail.

Practice Interactively

Related Lessons

Deflection and Decoy

Mating Patterns

Sacrifice and King Attack

Summary

When a tactic almost works, ask which line is missing. If one of your own pieces is in the way, look for a forcing move that clears it. If an enemy piece is defending along a line, look for a move that blocks that line — even at the cost of a piece.

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Next in this course

Double Check and Smothered Mate

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