An x-ray attack in chess is when a long-range piece — a rook, bishop, or queen — exerts its power through an enemy piece sitting on the same line, hitting a target on the far side. The piece in the middle doesn’t block the attack so much as get “seen through,” like an x-ray photo revealing the bone behind the skin. It’s how you win material that looks perfectly safe.
Let’s unpack how x-rays work, the two flavors (attacking and defending), and how they differ from their cousins the pin and the skewer.
The 10-second version
- An x-ray = a rook/bishop/queen exerting influence through an enemy piece to a target behind it.
- Attacking x-ray: your power passes through the front piece to win the more valuable piece behind it (often “pinning” the front one in place).
- Defending x-ray: your piece defends one of your own pieces through an enemy piece on the same line.
- It’s related to the pin and skewer — all three exploit pieces lined up on a single rank, file, or diagonal.
What is an x-ray attack in chess?
The whole idea rests on one fact about long-range pieces: rooks, bishops, and queens move in straight lines, and chess players think in terms of those lines. An x-ray happens when two or three pieces sit on the same line, and your piece’s influence reaches past the nearest enemy piece to the one behind it.
The classic attacking x-ray works like this: your bishop (or rook or queen) is aimed at an enemy piece. Behind that piece, on the same diagonal or file, sits something more valuable — a queen, say. Because the enemy can’t let that front piece move (doing so would expose the queen to capture), the front piece is effectively pinned in place by your x-ray. Now you can pile on more attackers and win it.
In the position above, the bishop on c3 looks down the long diagonal at the knight on f6. But the x-ray continues past the knight to the queen on h8. The knight is paralyzed — if it ever moves, the bishop captures the queen. So White pounces: the pawn on g5 attacks the frozen knight, and Black can’t save it. Play gxf6 and the knight falls; if Black tries to wriggle the knight away, Bxh8 wins the queen. The x-ray turned a “safe” knight into a doomed one.
How does an x-ray work on a file? (A second example)
X-rays aren’t just for bishops on diagonals — rooks and queens do it down files and ranks all the time.
Here White’s rook on d1 looks up the d-file at Black’s rook on d7. Directly behind that rook, on the same file, is the queen on d8. White’s rook x-rays through the enemy rook to the queen. The black rook is now under serious pressure: it’s tied to the d-file, because moving it would let the white rook slide up and hit the queen. This is the kind of pressure that wins games — you’ve immobilized a piece simply by lining up an attack that “sees through” it.
What’s the difference between an x-ray, a pin, and a skewer?
These three are constantly confused, so let’s nail it down. All three exploit pieces on the same line — the difference is which piece is in front and what happens.
- Pin: a less valuable enemy piece is in front, a more valuable one (or the king) behind. The front piece can’t move because it’s shielding the valuable one. (An attacking x-ray is essentially a pin where you then win the pinned piece.)
- Skewer: the reverse of a pin. The more valuable piece is in front; you attack it, it’s forced to move, and you capture the piece that was hiding behind it.
- X-ray: the broader concept — your piece’s power passing through another piece on the line. An x-ray can act like a pin (front piece frozen) or work defensively (see below). Think of “x-ray” as the family name; “pin” and “skewer” are specific siblings.
The simple memory hook: pin = valuable behind; skewer = valuable in front; x-ray = seeing through. When you spot any two enemy pieces on one line, your brain should light up — there’s almost always a tactic lurking.
What is an x-ray defense?
X-rays aren’t only for attacking — they’re a sneaky way to defend, too. In a defensive x-ray, one of your pieces defends another of your pieces through an enemy piece on the same line.
Imagine your rook is defending a passed pawn down a file, but an enemy rook sits between them. Your rook still “defends” the pawn in the x-ray sense: if the enemy rook captures the pawn, your rook recaptures, because the moment the blocker is gone, your line is clear. The enemy piece in the middle gave you a false sense that the pawn was undefended — but the x-ray says otherwise. This idea shows up constantly in rook endgames and is a favorite of endgame composers, who build entire studies around a piece defending “through” the enemy.
Why do x-rays matter?
Because they reveal value that’s hidden. A beginner looks at a piece and sees only what it attacks directly. A stronger player sees the whole line — including what’s behind the obvious targets. That shift in vision is worth a lot of rating points.
X-rays also underpin bigger combinations. The fearsome windmill, for instance, runs on a bishop that x-rays the enemy king down a long diagonal while a rook seesaws in front of it. Learn to see through pieces and you’ll start finding tactics that were invisible to you before.
A fun bit of history
The x-ray takes its name from medical x-ray imaging — the technology that lets doctors “see through” skin to the bones beneath. Chess writers borrowed the word in the 20th century precisely because the effect feels the same: your bishop or rook peers through a piece to strike what lies behind. The term is sometimes used a bit loosely (some authors use “x-ray” only for the defensive version and call the attacking version a “skewer” or “pin”), which is exactly why we’ve spelled out the distinctions above. Don’t worry too much about the labels in a real game — worry about the lines.
Common mistakes to dodge
- Only looking at what a piece attacks directly. Train yourself to follow the whole line — past the first enemy piece to whatever sits behind it. That’s where x-rays hide.
- Confusing the x-ray with a simple block. A friendly piece between two enemies blocks the attack. But an enemy piece in the middle is often just a thin curtain — your power may pass right through it the moment it moves or gets captured.
- Forgetting the x-ray cuts both ways. Two of your own pieces lined up against an enemy can be x-rayed in return. Check whether the opponent’s piece is also “seeing through.”
- Mislabeling the tactic and miscalculating. Whether it’s a pin, skewer, or x-ray changes who moves first and what you win. Get the geometry right before you commit.
Key takeaways
- An x-ray attack projects a rook/bishop/queen’s power through an enemy piece to a target behind it.
- Attacking x-rays freeze the front piece (pin-style) so you can win it or the piece behind.
- Defensive x-rays let one of your pieces guard another through an enemy blocker.
- It’s the family the pin (valuable behind) and skewer (valuable in front) belong to.
- The skill is line vision — always look past the first piece on any rank, file, or diagonal.
Keep climbing
The x-ray is pure long-range vision — the same vision that powers the brutal windmill and that you’ll need to read when a defender’s line gets cut in interference.
Next up: Browse all tactics · Also handy: what checkmate means and why king safety wins games.
Written and fact-checked by the Chess Lab Academy Editorial Team (AI-assisted, human-edited) · Every position verified with Stockfish 17 and checked against the FIDE Laws of Chess · Last verified 2026-06-25 · Sources · How we verify content.