In this series, we are looking at Rook and Pawn positions where the pawn is as far as possible from queening. Last time, I gave white a Pawn on b2 and cut Black's King off on the h-file. Those cases were relatively easy, however if you'd never tried to play them before, they might seem difficult. I am, of course, assuming that you already have some basic knowledge of Rook and Pawn positions and how to play them. If you don't know the Lucena position or the Phililidor position, the material I'm covering here will seem abstract.
So, this time, we will start out with the Pawn and the defending King one file closer. Take a look and see if you can find a way for white to win this. According to Tablebase, it's mate in 41 with best play, White to move.
Now I will demonstrate how to win this position. There are similarities with the previous example with the King on the h-file, but they are not identical. For one thing, Black's King is too close to just put the Rook on f4 and then push the Pawn to b4. That risks letting the game slip into a draw, and I'll show a little bit of why.
As was the case with previous examples, neither I nor the computer played with Tablebase accuracy. Where better moves were possible, I noted it in the game score.
Now, when we start placing Black's King at locations on the g-file other than g8, things get difficult rather quickly. The ideas of getting the Rook to the 4th rank or to b1 in order to advance the pawn don't usually work. In light of this, it will be necessary to introduce different strategic themes for advancing the pawn and making progress.
If we put Black's King on g7, Tablebase says that it's now mate in 47 with white to move. What I'm going to do here is play this position in the way that comes naturally to me, and then we will compare that with the line of best play. In the process, new strategic ideas will pop up, which I will discuss in the annotations and below.
The line of best play is given as a variation, starting with 1.Rf4. 1.Rf3 came more naturally to me. Either way, the thing you should take away from this example is the following:
Sometimes the Rook has to go in front of the Pawn!
There are different purposes served by placing the Rook in front of the Pawn. Sometimes it's there just to aid its advance. Sometimes it's there to shield the King from checks. This idea will pop up many times as we work through different cases.
Let's move Black's King once more, and put it on g4. This nullifies immediately any idea of playing Rf4 or Rf3, and the difficulty of the position is greatly increased. In fact, this is about as difficult as it gets. White to move, it's mate in 53. Black to move it's theoretically a draw.
As a practical matter, with this position between masters, Black is likely to hold a draw a good part of the time. On the white side of it, just face the fact that you can't play with Tablebase accuracy. If the game slips into a theoretical draw, just remember that your opponent isn't Tablebase either. He might botch it and let the game slip out of a draw. This happens a lot in practical play, and it is just a fact of chess.
So, here it is. It's me playing vs a chess engine at full strength. Neither of us were accurate, and where better moves were available, I noted it. It took me several tries to win this one without any help. I explain some of what is happening in the annotations.
I will show two more games with this position. The main line is me playing vs the chess engine , and the other line is the line of best play. In the line of best play, including the first move, the game goes through an astonishing 5 nodes where White has one and only one move that maintains the win.
Once again, the theme of maneuvering the Rook in front of the Pawn is present. It's a valuable tool that can help convert a lot of positions. I'll cover more on this in an upcoming post.