Moria and Lucena

From Wikipedia:
In the fiction of J. R. R. Tolkien, Moria (Sindarin for "Black Chasm") was the name given by the Eldar to an enormous underground complex in north-western Middle-earth, comprising a vast network of tunnels, chambers, mines and huge halls or 'mansions', that ran under and ultimately through the Misty Mountains. There, for many thousands of years, lived the Dwarf clan known as the Longbeards.

From Baby-Names-Meanings.net:
Lucena - Illumination. Light. Mythological Roman Goddess of Childbirth and Giver of First Light to Newborns. Also Refers to Mary As Lady of the Light.

Speak, friend, and enter. The magic word to open the door into rook endgames is Lucena, which is actually a class of positions with material of King, Rook, and Pawn against King and Rook.

The Pawn must be a non-rook pawn advanced to its seventh rank. The attacking king stands on the queening square of its own pawn. The attacking rook cuts off the defending king from the pawn by one file (e.g. pawn-file-king). The defending rook hinders the escape of the attacking king from the queening square.



The winning maneuver begins with a check from the attacking rook to create some breathing room for both the king and the pawn.
1.Re1+
If 1...Kf6, then 2.Kf8 and g8=Q on the next move. Note that if Black tries to checkmate with 2...Ra2 3.g8=Q Ra8+, 4.Re8 is conveniently available. If 1...Kd6, White may have to deal with a counterattacking king after 2.Re4 Kd5, but 3.Rg4 should win. So the generic case is
1...Kd7



Now comes the key move of the Lucena position.
2.Re4

The purpose of the move is to provide cover for the White King who must dodge a series of checks from the Black Rook. The White Rook will block the check just as the White King disconnects itself from defense of the pawn on g7. Hooper and Whyld's Oxford Companion to Chess (1992) attributed the phrase "building a bridge" to Aron Nimzowitsch.

Now, a typical sequence of moves would be:
2...Rh1
3.Kf7 Rf1+
4.Kg6 Rg1+
5.Kf6 Rf1+
6.Kg5 Rg1+
7.Rg4



As the attacking rook intercedes in this bridge-building maneuver, my mind drifts to the Lord of the Rings scene where the Fellowship of the Ring is running from the Balrog found in Moria. His fellows having safely crossed the Bridge of Khazad-Dum, Gandalf in the middle of the bridge turns to face the Balrog and shouts:

You cannot pass! I am the servant of the Secret Fire, wielder of the Flame of Anor. The dark fire will not avail you, Flame of Udun! Go back to the shadow!

You shall not pass!

Then Gandalf sunders the Bridge and the Balrog falls, but pulls Gandalf down with his whip. To the Fellowship, Gandalf's last words are, "Fly, you fools!"

It is not until the return of Gandalf the White in the Two Towers are we told what happened.

"[We fell] through fire and water. From the lowest dungeon to the highest peak I fought him, the Balrog of Morgoth. Until at last, I threw down my enemy and smote his ruin upon the mountainside. Darkness took me and I strayed out of thought and time. Stars wheeled overhead and every day was as long as a life-age of the earth. But it was not the end. I felt life in me again. I've been sent back until my task is done."

You can watch the epic battle here.

If Black chose to exchange rooks
7...Rxg4+
8.Kxg4
it would look as if Gandalf (the White Rook) and the Balrog (the Black Rook) fell into the abyss and disappeared, leaving the diminuitive Ringbearer to reach the queening square and win the battle for Middle Earth. Note that because of the first check in the variation, the Black King is separated enough from g8 that he cannot prevent queening.
8...Ke7
9.g8=Q

As useful as Lucena would seem, I have not actually used it in a tournament game. Of 425 tournament games I have played since 1991, zero have ended in a Lucena position. Three have ended in Philidor type draws. My other heavily Tolkeinized post parallels the Battle of Helm's Deep.