Skewer in Chess: the Tactic That Goes Through a Piece
A skewer is an attack along a line against a valuable piece which, when it steps out of the way, exposes another piece standing behind it. It is the reverse of a pin: in a pin the front piece is worth less and does not want to move; in a skewer the front piece is worth more and is forced to move, giving up the one behind.
How a skewer works
Like the pin, the skewer is the work of the long-range pieces: bishop, rook and queen. There are three pieces on the same line:
- the skewering piece, which attacks;
- the front piece, the more valuable one, which must move;
- the back piece, which is left exposed and gets captured.
The name comes from the kebab skewer: one attack runs through both pieces. You will sometimes hear it called an X-ray, although that term usually describes a slightly different idea (a piece exerting influence through another one).
Absolute skewer: the king in front
When the front piece is the king, the skewer comes with check. Your opponent has no choice: the king must leave the line, and the piece behind falls. This is the strongest form of skewer: there is no time to counter-attack, and the only ways out, when they exist, are capturing the checking piece or blocking the check with a protected piece.
Relative skewer
When the front piece is the queen or a rook, there is no check, and your opponent can try something else: protect the back piece, counter-attack or trade. Even so, a relative skewer usually wins material, especially when the skewering piece is protected.
Skewer vs pin
| Pin | Skewer | |
|---|---|---|
| Front piece | worth less | worth more |
| What it does | stays stuck | is forced to move |
| Who loses material | the front piece (or the back one, if the front moves) | the back piece |
| Pieces that do it | bishop, rook, queen | bishop, rook, queen |
An easy way to remember it: in a pin, the stuck piece is the one in front; in a skewer, the victim is the one behind.
The rook-endgame trick
Skewers are everywhere in rook endgames. The typical case: White's rook stands in front of its own pawn (on a8, with the pawn on a7), and Black's rook is behind the pawn on the a-file. If Black's king is on the wrong square, White has a shot: the rook leaves a8 for h8, and if Black's rook grabs the pawn, White's rook checks along the seventh rank and wins the rook with a skewer.
With Black's king on g7 or h7 the trick fails, because the king covers h7 (or is already standing there). That is why the defender in this kind of ending should keep the king on those squares. The last puzzle in this article shows the winning version.
💡 Tip: whenever your opponent's king and a valuable piece share a line with empty squares between them, look for a check along that line. This works for skewers and pins alike.
Where to look for skewers
Skewers appear in very recognizable situations. It is worth checking each of them whenever they come up:
- Kings in the center in the endgame. Once the queens are off, the king becomes an active piece and walks around the board. That is great for the endgame, but it exposes the king to rook and bishop checks that run through it and hit whatever stands behind.
- Open long diagonals. A bishop on b2 or g2 (or b7 and g7) sees across the whole board. King and queen on the same long diagonal are an invitation.
- Pieces at both ends of the same rank. Rooks and kings on the same rank with no pawns in between are classic targets for rook or queen skewers.
- Pawns about to promote. A skewer can also win a freshly promoted queen: if your opponent promotes on a square lined up with their own king, a rook or bishop can give check and take the new queen from behind.
A good way to train your eye is, after each of your opponent's moves, to trace the lines coming out of their king and see what stands behind.
How to avoid skewers
- Do not line up your king and valuable pieces on open diagonals, files or ranks, especially in the endgame, when the king walks around the center.
- Protect the back piece when the alignment cannot be avoided: a skewer gains little if the back piece is defended.
- Keep a block ready: a piece that can interpose on the check defuses an absolute skewer.
Skewer puzzles
Hint
The king on e5 and the queen on h8 are on the same long diagonal.
Show solution
1.Bc3+ Ke6 2.Bxh8
1.Bc3+ checks the king along the a1–h8 diagonal. The king must leave it, and 2.Bxh8 takes the queen.
Hint
Black's king and rook are on the same rank. The a-file is open.
Show solution
1.Ra5+ Ke6 2.Rxh5
1.Ra5+ checks along the fifth rank. The king moves away, and 2.Rxh5 takes the undefended rook.
Hint
White's rook is in the way of its own pawn. What if it leaves a8 for a square from which it can check along the seventh rank?
Show solution
1.Rh8
1.Rh8! threatens 2.a8=Q. If 1...Rxa7, 2.Rh7+ is a skewer: the king leaves the seventh rank and 3.Rxa7 wins the rook. If Black does not take the pawn, it promotes (after a check such as 1...Rf1+, just step out of check) and Black's rook will have to give itself up for it.
Frequently asked questions
What is the difference between a skewer and a pin?
In a pin the front piece is worth less and stays stuck; in a skewer the front piece is worth more and is forced to move, leaving the back piece to be captured.
Which pieces can skewer?
The bishop, rook and queen, the only pieces that attack along lines.
Are a skewer and an X-ray the same thing?
Many players use the words interchangeably. Strictly speaking, "X-ray" describes a piece exerting influence through another (for example, a rook defending a square behind an enemy rook), while the skewer is the blow that forces the front piece to move.
Where do skewers show up most?
In endgames, when the kings come out to the center and get lined up with rooks and queens. See also the overview of chess tactics.