Endgame Fundamentals - The Lucena Position

Introduction

The Lucena Position is a famous endgame position in which one side has a rook and a pawn while the other side has just a rook. This position is theoretically won for the attacking side, but requires immensely precise and accurate technique. Let's take the following Lucena position below:

As we can see, white has a passed c7 pawn that is about to promote. If the white King steps out of the way black will start to give endless checks. Here is a detailed step-by-step way to win this endgame:

1. Cut the King

While there are many winning moves here, the easiest is to first cut the king. Hence Re1 is the best move here. Now the Black king cannot come close to the pawn, and this will be crucial later on.

2. Building the 'Bridge'

Say Black just waits with the rook with Rc2. Now we play a key move that is characteristic of the Lucena position. We want to move our king out of the way, but this will result in checks. One way to escape the endless checking is to potentially block with the rook. That's why we play the key move Re4!

The characteristic move of the lucena position, building the 'bridge' and eventually paving way for the promotion of the pawn.

3. Use this 'bridge' to walk the king out and promote the pawn

With this bridge, we are now ready to walk the king out. Let's say black waits on the c file with Rc1. Now we will walk the king out with Kd7 (b7 also works too). Black will give Rd2+, but now we come to c6. Rc2+, Kd6 (keeping contact with the pawn). After Rd2+ Kc5 Rc2+ now we see the purpose of the bridge. We can now play Rc4!, shielding the king and paving the way for the pawn.

Black has nothing better than to trade, and now we see after the trade the crucial placement of the Black king. The king is one tempo short --- if the king were on e7 this would not work at all. White queens the pawn and wins easily.

This is a brief overview --- if you want to learn more I'd recommend the STLCC lecture on Lucena and Philidor by Yasser : https://www.youtube.com/watch?v=yrdgbB_dhg0

[Variant "From Position"]
[FEN "2K5/2P2k2/8/8/8/8/1r6/7R w - - 0 1"]
1. Re1 Rc2 2. Re4 Rc1 3. Kd7 Rd1+ 4. Kc6 Rc1+ 5. Kd6 Rd1+ 6. Kc5 Rc1+ 7. Rc4