What is a skewer in chess?
Updated
A skewer is an attack along a line on a valuable piece with another piece behind it. When the valuable piece moves away, you capture the one behind. Only bishops, rooks and queens can skewer, and the most forceful skewers go through the king, because the king has to move.
Skewer or pin?
Both attack two pieces on one line. The difference is which piece stands in front.
| Pin | Skewer | |
|---|---|---|
| Front piece | Less valuable | More valuable, or the king |
| What it does | Stays put, because moving exposes the piece behind | Has to move |
| What you win | Often the front piece | The piece behind |
Skewering the king
A king in the open makes a good target, and in endgames kings walk out to the middle of the board. Here the black king on e5 has its rook on e8 directly behind it on the file.
The king can't stay on the file, because the rook's line still runs through it. Wherever it goes, it is too far away to guard e8, so Rxe8 wins a rook for nothing.
Bishops do the same on diagonals. After Bc4+ the king must leave the diagonal, andBxg8 wins the queen. She can't capture the bishop, because her own king stands in the way.
Skewering the queen
A skewer doesn't need a check. After Bf3 the bishop attacks the queen on c6 with the rook on a8 behind her, and Black has no good answer:
- If the queen moves off the diagonal, Bxa8 wins the rook.
- If she captures with Qxf3, then gxf3 wins the queen for a bishop.
- If she guards the rook with Qc8, then Bxa8 Qxa8 still gives White a rook for a bishop: 5 points for 3.
Try it: find the skewer
White to move. Your rook on a1 is selected. Two rook moves give check, but only one wins the queen on d8. Which one?
Show answer
Rd1+. The king must leave the d-file, and Rxd8 wins the queen. The other check, Ra5+, loses the rook to Qxa5, because the rook lands on a square the queen attacks.
How to spot a skewer
- Look for two enemy pieces on one line with nothing between them, where the front piece is the king or is worth more than the piece behind.
- Watch the king in the endgame. Once it walks to the middle, check which pieces stand behind it on each rank, file and diagonal.
- Make sure your attacker is safe. A queen in front can capture a rook or bishop that attacks her, unless it is guarded. That is why the g2 pawn matters above.
How to defend against a skewer
Keep your valuable pieces off the same open line, and keep the piece behind defended. One square can decide it. This position is the first example with the king on e6 instead of e5:
If you are skewered through the king, you may have a choice of squares, so pick one that guards the piece behind, as Kf7 does here. If the front piece is not the king, look for a move that takes it to safety and guards the piece behind at the same time.
Pins and skewers both use one line. A discovered attack opens a line that was closed.
Questions people ask
- Which pieces can skewer?
- Only bishops, rooks and queens, because a skewer needs a line that runs through one piece to the piece behind it. Knights, pawns and kings can’t do it.
- Does a skewer have to be a check?
- No. A skewer through the king is the strongest kind, because the king must move, but you can also skewer a queen or a rook.
- What if the piece behind is defended?
- Then capturing it is a trade, not a free win. It can still pay if your piece is worth less than the one you take, as when a bishop wins a rook.