Philidor - 1777, Black to move and draw
Philidor's Drawing Method in the R+P vs. R endgame can be summarized as follows, given the defender's King is in front of the pawn on the queening square:
1) Defender prevents his opponent's King from advancing to the 6th Rank. The superior side is forced to push his pawn to use it as a shelter for the King to cross the sixth rank. 2) When the pawn moves to the sixth, defender shifts his Rook to behind the superior side's King to give checks. 3)With pawn on the sixth, Superior side cannot escape checks from Behind - Draw!
Let's examine this move by move:
"Defender prevents his opponent's King from advancing to the 6th Rank." It is clear that White, in order to make progress, will need to advance the pawn to screen the King from the Rook. Exchanging Rooks leads to a drawn endgame. In fact, any Rook move on the b-file draws except the obvious 1...Rb7?? (2. Rxb7 +-), and 1...Rb5? which allows 2. Kg6! and if 2...Rb6+ 3. f6 with mate threats wins, or if 2...Rb1 3. Ra8+ Ke7 4. f6+ wins as well.
Only real try.
"When the pawn moves to the sixth, defender shifts his Rook to behind the superior side's King to give checks." Black now shifts his Rook as far away from the White King as possible, preparing to give harrassment checks.
3. Kg6 Rg1+ 4. Kf5 Rf1+ 5.Ke6 Re1+=
Of course, with White on move, Black is lost due to the mate threats White can generate:
1. Kg6! Rc8 (if 1...Rb1 2.Ra8+ Ke7 3. f6+ Ke6 4.Re8+ Kd7 f7 +-.)2. f6 Kg8 3. Rg7+ Kf8 4. Rh7! Kg8 5. f7+-.
It's also important to know that Black can survive if instead White has a Knight or Rook pawn. The mechanism just shown no longer exists, as White is short one rank to play his Rook maneuver. This defense is known as the "Back Rank Defense".
It is certainly worth the time to understand these simple Rook endings and know them intimately, so when they appear in your games (they will), you will know how to proceed to defend or win the position. Next, we'll look at the other most well-known Rook Ending - Lucena's Position.
Source:Fundamental Chess Endings, Just the Facts!