Hello everyone and welcome back to the Endgame Column. As we continue our journey through the various endings, we will be adding more pieces to the board, eventually to the point that they will start getting fairly complicated. But for now, we will be covering various simple, yet crucial endings.
In the current column, we will be looking at a king and rook versus a king and one pawn. At first glance, it may appear as though the rook ought to win almost every time. However, the rook's inability to move diagonally can actually cause some problems for the rook where he may not be able to win. With an extreme rare few exceptions, the rook will almost never lose, but in many cases, the win is not as obvious as it may look.
We will be covering a number of important concepts in the rook versus pawn ending. These include
Cutting off the King
Underpromotion
Shouldering
Scenarios Where the Pawn Wins
Now it should be noted that for the side with the rook, if his king can get in front of the opposing pawn, it is a win for the rook. Therefore, in our examples, the king, for the side with the rook, will typically be far away from the pawn.
Cutting off the King
We start with a critical concept that will not only be important here, but also in upcoming articles, such as the next few on rook versus two pawns and rook and pawn versus rook. It is about cutting off the opposing king. If you can force separation of the kng and the pawn early enough, the side with the rook wins.
Here, we see the black king on the 6th rank and his pawn on the 4th rank. The white king is all the way back on g8. There is no way for the white king to chase down the pawn, and so the rook must do the work.
However, if everything is moved down just one square, the position is a draw.
So we can conclude that for this procedure of cutting off the king to work, it must be done, from the perspective of the player with the rook, on the 5th rank or further. Cutting the king off on the 4th rank or anywhere closer to where the pawn needs to get to promote is only a draw assuming the king is out of play and the rook has to do all the work.
It should be noted that if the king can get anywhere in front of the opposing pawn, then the side with the rook wins.
Underpromotion
One unique thing about rook versus pawn endings has to do with the way a player mates with a rook. If you have a king and a rook and your opponent has just the king, where do you have to mate him? The answer is against the edge of the board, whether it be the a-file, h-file, first rank, or eighth rank.
Well, promotion also occurs on the edge of the board, and sometimes, when the opposing king is close to the pawn but not caught up to it, the side with the pawn may have to underpromote due to a checkmate by the rook.
The Exception to the Rule
Like many endings we will be seeing in upcoming articles, there are always exceptions, and here it is no different. The position shown in the previous example is only a draw if Black's pawn is a center pawn, bishop pawn, or knight pawn. Black is lost if it is a rook pawn.
Shouldering
Shouldering is a critical concept to understand. In chess, the shortest distance between two points isn't always a straight line. For example, a king can get from f5 to f1 in a straight line (f5-f4-f3-f2-f1) in the same number of moves as a crooked line, such as f5 to e4 to d3 to e2 to f1, and that "wedge" that is created by taking that route can impede the opposing king's path, which in some cases, can be critical. In the following example, we don't see that exact "V-shaped" movement, but we do see the king not moving in a straight line up the board.
This type of movement must always be considered, even if it means blocking your own pawn temporarily in the process.
Scenarios Where the Pawn Wins
In a few cases, a far-advanced pawn can actually defeat a rook if the rook cannot get behind the pawn or on the rank of the pawn's promotion.
The following is a fairly common position in endgame books as it combines the scenario of the pawn winning with underpromotion.
Problems
Problem 1 - We will talk about rook against two pawns in the next article, but what you learned in rook against one pawn can be applied here. White to move and win.
Problem 2 - The pawn is pretty far from promotion, but with correct play, Black can hold the position. Black to move and draw.
Problem 3 - White to move and win
Problem 4 - The following position is exactly the same as Problem 3 with the lone exception that every piece was moved to the right one square. With White to move, can White win with the exact same approach as the solution to Problem 3? What would be the result if White does take this approach? Which squares must the white king avoid?
Solutions
Problem 1 - White can ignore the h-pawn as it is too far back. The key is cutting the black king off by going to the 5th rank, and if the h-pawn ever advances to the 5th rank, you simply capture it, and otherwise, you follow the same idea as what was covered earlier. 1.Rf5 a3 2.Rf3 a2 3.Ra3 and White wins.
Problem 2 - Here, Black must use shouldering to survive. 1...Ke4! is the only move. If 2.Re1+, then 2...Kf3 3.Kd4 g3 and the white king is shouldered out and the draw is simple for Black. If instead 1...g3?, then 2.Kd4 Kf4 3.Rf1+ followed by 4.Ke3 and the win is elementary for White.
Problem 3 - This problem should be solved by process of elimination. 1.Ke7? 2.Rc1 f8=Q 3.Re1+, 1.Kd5? 2.Rf6, and 1.Kf5? Rc1 followed by 2...Rf1 all draw. The only winning move for White is 1.Ke5!, when Black cannot get behind the pawn or to the back rank, and so he must continue to check White. After 1...Rc5+ 2.Ke4 Rc4+ 3.Ke3 Rc3+ 4.Kf2 Rc2+ 5.Kg3 Rc3+ 6.Kg4 Rc4+ 7.Kg5 Rc5+ 8.Kg6 Rc6+ 9.Kg7 and White wins as Black is out of checks and cannot stop promotion of the f-pawn.
Problem 4 - White cannot win due to two poisoned squares. After 1.Kf5 Rd5+ 2.Kf4 Rd4+ 3.Kf3 Rd3+ 4.Kg2 Rd2+ 5.Kh3 Rd3+, the move 6.Kh4?? is a blunder and loses to 6...Rd1!!. Both 7.Kh5 Rg1 8.Kh6 Ke7 9.Kh7 Kf7 and trying to shoulder Black out with 7.Kg5 Rg1+ 8.Kf6 Ke8 win for Black. It is only two squares that the king must avoid, and that's h4 and g4. But that is enough to not allow White to win as White needs to get his king to the other side of the pawn, but he can only cross the g-file at the squares g1 or g2 as otherwise, the black rook can get behind the pawn and draw the game. So if the white king ever goes to g5 or g6, then ...Rd1 draws, while if it ever goes to g4 or h4, then Black wins by going ...Rd1. That creates enough of a barrier such that White cannot reach the winning square for his king, which is h7.
Comments