What is the Philidor position? It depends on what kind of endgame you’re talking about. With queen versus rook, it looks something like this:
Here are the key elements to remember:
- Attacking king is two diagonal squares from corner
- Rook is one diagonal from that corner
- Queen is a knight’s move from both its own king and the rook
- Defending king is next to that corner and a knight’s move from other king
Another point is that black needs to have the move, in order for white to most quickly win. What if it’s white’s move? Follow this procedure:
- Move queen to the center square that checks the defending king
- Move queen to corner that almost completes a triangle of queen moves
- Return queen to the original (Philidor position) square
The defending king needs to move to the eighth rank (allowing Qa8+) for moving Kh6 allows Qh4#. The above is a common triangulation method of losing a move.
What can Black Do?
In the queen-versus-rook Philidor, the defending king has only one legal move, and it results in the queen pinning the rook and capturing it on the next move. Let’s look at possible rook moves:
Short moves by the rook don’t work. The one in which the rook is not immediately lost, Rg8, results in immediate mate: Qh5#. Let’s look at longer rook moves, beginning with the ones that pass the attacking king, away from the queen, down the g-file:
Rg4 quickly loses the rook to Qh5+. With Rg2, it’s quickly lost to Qe4+.
What about Rg3? My favorite technique, in that case, begins with Qh5+. After black plays the forced Kg8, white plays Qd5+ giving us this position:
Notice that Kf8 results in immediate mate (Qd8#) and that as long as the queen is on the a8-h1 diagonal, the defending king cannot ever move to h6 without the devastating Qh1+.
The two key forking squares, for the white queen to get to in the above position, appear to be b8 and c7, one of which needs to be obtained while checking the black king. In reality, only one of those two is needed: b8. The winning method is simple. The white queen checks on one of the following two squares (depending on the black king moving to h8 or h7): a8 or b7. The longest delay of checkmate comes from the black moving Kh8. The winning combination is then as follows:
1) Qa8+ Kh7
2) Qb7+ Kg8 (or Kh8)
3) Qb8+ winning the rook
So that leaves only one more possibility, if the rook moves down the g-file: Rg1, seen here:
The technique is similar to the previous one: The queen takes the a8-h1 diagonal with Qe4+. Notice the Kh6 results in immediate mate (Qh4#). Whether the black king moves to g8 or h8, the queen then checks at a8, forking the rook on the next move (Qa7+).
Notice that a black king at h8 and the rook at g8 allows Qh1#, when the queen has that a1-h8 diagonal. Do you see how important is that attacking king on that particular square (two diagonal moves from the corner)?
Let’s now look at rook moves along the seventh rank, moving to the left in the following position (the original Philidor position):
The first three rook moves to the left result in its immediate capture, while Rb7 results in an immediate fork: Qe4+. That leaves Rc7 and Ra7. We’ll begin with Rc7:
The e4 square looks promising for the queen, for it gives access to both a8 and h1. Keep the queen on that a8-h1 diagonal and check the king again, on either g2 or h1, depending on whether the black king has moved to g8 or h8. As the queen gives checks while it approaches the h2 forking square, black has no way to avoid that loss of the rook, unless the a8 mating threat is ignored.
That leaves only one more possible move for black, from the Philidor position: Ra7.
This may be the best defense for black, for it takes away the a8 from the queen. In the above position, I would aim for the forking square g1. It can be obtained by moving the queen to the following squares: h5, g4, h3, g3, h2, and finally the key square: g1.
The black king cannot move to f8 without allowing the queen to mate at b8 or c8 and the rook interposing with the black king at h8 allows a similar mate. Look at the following pattern of queen moves:
Notice the queen’s zig-zagging moves above. It’s not a simplistic pattern, for g2 is avoided, for good reason. The queen needs to keep an eye on either b8 or c8, until it reaches g1. With the black king at g8, a check by the queen moving to g2 would be a mistake, for the black king could then move to f8, leaving no more reasonable checks for the queen.
Why Bother Looking at a Queen-Versus-Rook Endgame?
It’s highly unlikely that you’ll ever play a game that gets to the queen-vs-rook ending. But notice how the winning solutions were found. It was not random checks, trying to happen onto a fork or mate. The reasoning was logical, finding key forking squares and ideal checking squares for the queen. In your end games, look for the key points, the essence of the type of ending you find yourself in.
In the queen-versus-rook endgame, the Philidor is an important key position. If you ever find yourself in this kind of endgame, with the queen, aim for that corner position, for even the best defender cannot remain alive when you use logic in finding the key squares.
Derek Grimmell calls this the trapezoid, a key position in the queen-versus-rook endgame. Although it may look innocent enough, black has no move that does not quickly lose.
The queen can be a powerful fighter during much of the game. But in the opening be careful about bringing the queen out too early, for it might be a target of your opponent’s minor pieces and pawns . . .
Some of the movies with chess games are indeed realistic, while others are not. In Casablanca it was realistic, for Humphrey Bogart was a good chess player and surely would not have allowed any glaring mistake in the setup of the board; quite likely he set up the position himself.