How to win the Lucena position: build a bridge
Learn to win rook and pawn against rook from the Lucena position: drive the king away, build a bridge with your rook on the 4th rank, walk your king out and block the checks.
Build a bridge
This is the Lucena position. Your king blocks your own pawn, and Black's rook on the d-file stops it stepping out to the left. The plan: send the black king further away, put your rook on the 4th rank and walk your king out.
Play Rg1+: the check drives the black king one more file away, to the h-file, so your king can step out by f7. Rg1+ Kh7
1… Kh7 Kh7 is Black's best. Kf6, next to the pawn, looks natural but loses at once to Kf8: the next line shows why.
Now the bridge: play Rg4. From the 4th rank the rook will come to e4 and block the checks once your king has walked down to the 5th rank. Rg4 Rd1
2… Rd1 Black waits with Rd1: the rook stays far away, ready to check your king from behind.
Your king can step out now: play Kf7. The black king on h7 no longer covers f7. Kf7 Rf1+
3… Rf1+ Black's only resource is to check from behind: Rf1+.
Walk towards the bridge, staying next to the pawn: play Ke6. Ke6 Re1+
4… Re1+ Another check from behind, Re1+.
Play Kf6: keep stepping down the board beside the pawn, towards your rook. Kf6 Rf1+
5… Rf1+ Rf1+ again: Black keeps checking, it has nothing better.
One more step: play Ke5. Your king has reached the 5th rank, one above the bridge. Ke5 Re1+
6… Re1+ Re1+, the last check.
Block it: play Re4. The bridge is complete: your king guards the rook, so the checks are over and the pawn goes through. Re4 Rxe4+
7… Rxe4+ Black's best now is to trade rooks with Rxe4+: the pawn can't be stopped, but taking back costs you a move.
Take back: play Kxe4. Kxe4 Kg7
8… Kg7 The black king comes as close as it can, but the pawn is a step ahead.
Play e8=Q: the pawn queens, and the win is yours. e8=Q
That is the bridge: drive the king away, rook to the 4th rank, walk the king down beside the pawn, block the last check. Trading rooks does not help Black.
When the king steps up: Kf8!
Back to the start: after Rg1+ the natural reply is Kf6, next to the pawn. It loses at once.
Play Kf8: your king steps out behind the black king. Black's rook can't check along the f-file, because its own king on f6 is in the way. Kf8 Re2
1… Re2 The pawn can't be stopped now, so Black puts the rook behind it, Re2: when the pawn queens, the rook takes the queen. That is Black's best practical try here.
Play e8=Q all the same. After Rxe8+ Kxe8 you have king and rook against king: the rook checkmate you already know. e8=Q
With the black king on f6 there is no bridge to build: Kf8 and the pawn queens, and the most Black can do is give the rook for the queen. That is why Kh7 is Black's best answer to Rg1+.
Key ideas
- Your king stands in front of the pawn on its 8th rank, the pawn on the 7th, and your rook cuts the enemy king off. That is the Lucena position: a win.
- First drive the enemy king one more file away with a rook check, so your own king can step out on that side.
- Then put your rook on the 4th rank: that is the bridge.
- Walk your king out and down the board while the enemy rook checks it.
- When the king reaches the 5th rank, the next check is blocked by the rook on the 4th rank, and the pawn queens.
Common mistakes
- Stepping the king out before the rook is ready: the checks never stop.
- Blocking with the rook too early (Rf4 with your king on e6): the rook is not protected and is simply taken.
- Walking the king away from the pawn (Kd5 instead of Kf6): the rook takes the pawn.
- Leaving the rook where the enemy rook or king can take it.