|Position 1: Can Black save the game regardless of the move?|
If you still have vague recollections of the times when we talked about a rook-pawn on the 6th rank, then this will be easy. Here, Black draws by re-deploying his rook to the 6th rank to set up a Vancura Position.
We give White the first move here (although there is no difference with Black to move):
Black must find a way to get his rook to the 6th rank. I hope you remember that keeping the rook behind the pawn doesn't work: 1... Ra2? 2. Ke4 Ra1 3. Kd5 Ra3 4. Kc6 Ra1 5. Kb6 Rb1+ and now the king has a shelter from the checks (this won't work if the pawn were on the seventh rank!) 6. Ka7! Re1 7. Rc8 (releasing the White rook) threatening Rc7, Kb7 followed by promotion of the pawn.
Not giving White a chance to activate his rook. This is stronger than 1... Re1 2. Ra7+, and although Black can still draw with 2... Kg6 3. Rb7 Ra1 (discouraging any pawn advance), he might also fall for traps like 2... Kg8?? 3. Rb7 Ra1 4. a7 Ra2 5. Rb8+! with promotion on the next move.
2. Ke4 Rf6 (D)
With a pure Vancura Position; Black will just shuffle his rook along the 6th rank and check the White king if he gets too close to the pawn. Here are the links to the Vancura Position and the Pawn on the 6th rank to familiarize yourself if you haven't done so.
Our second position:
|Position 2: Black to play, can he save the game?|
If it were White to move it would be an easy Lucena Position: 1. Rg1+ followed by 2. Rc4 and the "bridge building" comes soon after.
What if it were Black to move? Fortunately for him, two factors contribute to him being able to hold the draw in this case:
- His king is on the short side of the board, and cut off by only one file
- His rook is already positioned on the long side of the board with sufficient checking distance.
Black employs the side-rank defense (the side-rank defense, as well as the long/short sides of the board, are discussed in this link) to save himself:
If Black's king were cut off by two files White could hide on f2.
3. Kd6 Ra6+
4. Kc5 Ra7
White cannot approach Black's rook without hanging his pawn. And not 4... Ra5+?? 5. Kb5 when Black's checking distance has been destroyed.
For your information, I recently found out that there is a fancy name for the side-rank defense: The Karstedt Maneuver. To quote from Bernd Rosen in his book "Chess Endgame Training", "With the Karstedt Maneuver, the defender's king has to move to the short side in order to allow the rook enough space for side attacks. This defensive procedure only works if there is a distance of at least three files the king of the side with the pawn and the defender's rook."
With that in mind, we move on to the third position:
|Position 3: Black to move, can he still draw?|
With the Black rook now on b2 rather than b1, the side-rank defense no longer works because of insufficient checking distance (the rook is less than three files away from the king). White wins this easily.
2. Kd7 Rb7+
3. Kd6 Rb6+
Black cannot stop the pawn from promoting.
And with that we're done with another rook endgame analysis. All the best for the year ahead!
Practice 1: http://nushsblackknights.blogspot.com/2014/12/rook-endgame-practice-1.html
Practice 2: http://nushsblackknights.blogspot.com/2014/12/rook-endgame-practice-2.html
"Silman's Complete Endgame Course" by Jeremy Silman
"Rosen's Chess Endgame Training" by Bernd Rosen