Rooks belong behind passed pawns: your own, to support them, and the opponent’s, to stop them. Behind the pawn the rook gains scope with every step the pawn takes, while a rook in front of the pawn only loses it.
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Siegbert Tarrasch wrote the rule more than a century ago: rooks belong behind passed pawns. You have a pawn on a6, two steps from queening, a rook on c1 that does nothing for it and a king on b3. The black rook on a8 stands in front of the pawn; the black king on g7 is far away. Fourteen moves to win.
What you will learn
01Why a rook behind its pawn gets stronger with every pawn step, and a rook in front gets weaker.
02How the black rook on a8 becomes a prisoner of the a-file.
03The same rule in defence: get behind the opponent's passer.
The technique
Put the rook on a1, behind the pawn. From there it protects the pawn all the way up, and as the pawn advances the rook sees further along the file. The black rook, by contrast, must stay on the a-file, because the moment it leaves, the pawn runs. One rook is free, the other a prisoner. Now the king walks up the b-file; the black rook cannot check it away without leaving the a-file, and when the king reaches the pawn the rook on a8 is attacked and the pawn promotes.
Where it goes wrong: pushing a7 at once. The pawn and the black rook freeze each other, your own rook is still on the wrong file, and the black king gets time to walk over, after which the win needs precise rook manoeuvres. The other mistake is checking along the seventh rank: checks that change nothing are moves given away.
How to practise it
Play White. The first move is a rook move and it is not a check. After that, walk the king and only touch the pawn when the king is beside it. Promoting ends the drill, and fourteen moves is enough with a few to spare.
Rooks belong behind passed pawns, yours and your opponent's. Behind its own pawn a rook supports every step; behind an enemy pawn it attacks it and ties the defending rook down.
Does the Tarrasch rule always apply?
Not always. With the pawn far back, or the kings close to it, a rook in front or at the side can be fine, and sometimes a rook on the seventh rank matters more. It is the default to check first, not a law.