Collinear Move

A collinear move is when your piece and an enemy piece face each other on a line (a file, rank, or diagonal), and instead of capturing that enemy piece you move your own along that same line to a different square. Capturing the piece you face looks natural, but advancing along the line without taking it is sometimes far stronger.

Why a Collinear Move Is Strong

When two pieces face each other on a line, the first thought is usually to capture. But that capture often amounts to a plain trade, and advancing along the same line without taking can be worth far more. The square you land on is the point: from there your piece often strikes on a different line, hitting a king or a valuable piece that had nothing to do with the file you were sharing.

Here is a middlegame from this site's puzzles (White to move). On the f-file, the white rook (f1) and the black rook (f8) face each other.

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Rxf8 takes the black rook, but Black recaptures and it ends in a trade. Instead, White does not take the rook and slides along the same f-file to f7. The first move is Rf7+.

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Rf7 stops one square short of the f8-rook instead of taking it. From there it checks the king on h7 along the seventh rank rather than the f-file it had been sharing. Black has only two replies, and both are mated next move: taking with the rook (Rxf7) runs into Qxf7#, and moving the king (Kg8) into Qg6#. The puzzle's main line is Rxf7 Qxf7#.

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Rf7+ Rxf7 Qxf7#. Everything hinged on the first move. Instead of taking the f8-rook it faced, the rook advanced along the same file and stopped in front of it. A capture would have ended in a single trade; declining it and taking the seventh rank made mate. That is a collinear move. Whenever you face an enemy piece on a line, it pays to check whether advancing along that line beats taking.

How to Spot a Collinear Move

When your piece and an enemy piece face each other on a line (file, rank, or diagonal), look for an option other than the capture. Check whether advancing along that line, without taking, lands you on a square that does more. The test is what the new square attacks: if it creates a check or hits a valuable piece on some other line, the quiet advance beats the capture. The piece you face is not only there to be taken. Sometimes it is just the reason you were looking at that line in the first place.

Collinear Moves by Our Numbers

This site's puzzle DB tags 305 puzzles as collinear move (measured July 2026). That is a thin slice next to the everyday motifs: fork alone carries 17,829.

By rating, 53% of collinear-move puzzles are rated 2000 or above, and only 2% are below 1200 - a strong tilt to the high end. Because you have to hold back the natural capture and find the counterintuitive move that advances along the line instead, it is one of the harder patterns to notice.

Collinear moves also overlap often with other tactics. Discovered attack (20.3%) is tagged alongside it especially often: the very move that advances along the line, instead of capturing, frequently opens the line of another piece behind the mover (a discovered attack). Double check (5.6%) overlaps for the same reason.

For the Defender

• Do not relax when pieces face off. When one of your pieces faces an enemy piece on a line, the opponent may slide along that line instead of capturing. Do not assume they will just take.
• Check what the landing square attacks. The danger comes from the other line the advancing piece reaches from its new square, like the seventh rank in the example above. Look at the squares the opponent can slide to, and guard them in advance, block the new line, or move the king or valuable piece off it.
• Capturing the piece that moved in is not automatically safe. Taking it helps only if the opponent has no stronger reply to the capture. In the example above, Rxf7 removes the rook, but the queen recaptures on f7 with mate. And if the advance gives check, you have to answer the check first.

References

• Lichess, puzzle theme Collinear move (the source of this site's puzzle tags). https://lichess.org/training/themes
• Example position: Lichess puzzle 2Aewc (CC0). https://lichess.org/training/2Aewc
• Statistics: scripts/analyze-collinear-move-stats.mjs, results recorded in docs/data/collinear-move-stats.md.

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Start training: Collinear move training

Related: Discovered attack · Double check · All tactics