ChessDays

Back-rank mate and how to stop it

Updated

A back-rank mate is checkmate along the first or last rank: a rook or queen checks the king on its home row while its own pawns block the way out. To stop it, move a pawn to give the king an escape square, or keep a rook or queen guarding the rank.

What a back-rank mate looks like

The king on g8 sits behind three pawns that haven't moved. They shelter it from attacks from the front, but they also take away its way out. Once a rook reaches the rank, the king has nowhere to go.

White: king g1, rook a1. Black: king g8, pawn f7, pawn g7, pawn h7.
White to move. The rook can run up the open a-file.
White: king g1, rook a8. Black: king g8, pawn f7, pawn g7, pawn h7.
After Ra8#. The rook covers f8 and h8, and the pawns fill f7, g7 and h7.

It works the same way against White, with a king on g1 behind pawns on f2, g2 and h2. Castlingon the kingside puts the king in exactly this kind of spot.

Try it: give the mate

White to move. Either rook can reach the back rank, but only one gives mate. Tap a rook, then tap a dot on the top row.

Show answer

Rd8#. The other try, Ra8+, fails because the bishop on b7 takes the rook with Bxa8. Always check whether the square you land on is guarded.

When the rank is guarded

A guard on the back rank doesn't always save the king. Here Black's rook on e8 is protected by the queen, but White has two pieces aimed at e8 and the king still has no way out.

White: king g1, queen e2, rook e1, pawn f2, pawn g2, pawn h2. Black: king g8, queen d7, rook e8, pawn f7, pawn g7, pawn h7.
White to move. Queen and rook line up on e8, and only Black's queen guards it.
White: king g1, rook e8, pawn f2, pawn g2, pawn h2. Black: king g8, pawn f7, pawn g7, pawn h7.
After Qxe8+ Qxe8 Rxe8#. White's queen is gone, but the rook mates on the back rank.

Qxe8+ takes the rook with check. Black's only legal move is Qxe8, and thenRxe8# is mate. White gave up a queen but took a queen and a rook, and the game is over anyway.

How to spot a back-rank mate

How to stop a back-rank mate

There are two reliable defences, and it pays to use one before the threat appears.

1. Make an escape square

Moving one of the pawns in front of the king gives it a square to step to. Now Ra8+ is only a check: the king replies Kh7, and the game goes on.

White: king g1, rook a1. Black: king g8, pawn f7, pawn g7, pawn h6.
With the pawn on h6, the king has h7 to run to.
White: king g1, rook a1. Black: king g8, rook c8, pawn f7, pawn g7, pawn h7.
With a rook on c8, Ra8 just loses the white rook to Rxa8.

2. Keep a guard on the rank

A rook or queen on the back rank can capture anything that lands there, as the second diagram shows. The danger comes when that piece leaves to go hunting. Before you move your last guard, ask what happens if a rook lands on your back rank next move.

Try it: save the king

Black to move. White threatens Ra8 mate. Tap one of the pawns in front of your king and move it to make an escape square.

Show answer

Any move of the f-, g- or h-pawn works, because each one opens a square on the seventh rank. After that, Ra8+ is no longer mate.

Questions people ask

Can a queen give back-rank mate?
Yes. A queen moves along ranks just as a rook does, so she can give the same mate.
Does a back-rank mate only happen on the eighth rank?
No. The back rank is the row each player’s pieces start on: the first rank for White and the eighth for Black. It can happen to either side.
Should I always move a pawn to stop it?
Only when you have time. A pawn move in front of the king is a quiet move, so make it when nothing more urgent is happening, and before your last rook leaves the back rank.