Tuesday, September 30, 2014

The Longest Win of the Week

It's time to get back into looking at some endgames, and the best way to start is to download The Week in Chess  (TWIC) and sort the games according to how many moves were played in descending order. The latest TWIC is number 1038 and Mark Crowther has been running the site for over 20 years now, an amazing achievement and a great service to chess.

Anyway, once downloaded I like to look through some of the longest games, and see if there are any endgames which interest me. In the latest edition, I saw a game between A. Bergougnoux(1895)-J. Hebert (IM 2378) which reached the following position:

Like most club players, I'm guessing my knowledge of rook endings is pretty patchy. This game ended in a win for black, and my first thought was why isn't this is a draw? So I went to Averbakh's "Comprehensive Rook Endings" and looked at the section on where a rook fights against rook and doubled pawns. Here's what the Russian Grand Master and endgame expert has to say about these types of positions:

"Compared with the other forms of pawn structure, doubled pawns are less dangerous. We will first consider examples where the defenders king stands in the way of the pawns. In this case the result is normally a draw"

Ok, that is pretty much the same for rook and pawn versus rook endings, and it describes the position above. Averbakh then goes on to say that a passive rook, or when the defending king isn't in front of the pawn can affect the result. The examples he uses are excellent!

In this position, the defender has to use the same procedure as if the d4 pawn wasn't there. That is, wait till the pawn reaches the 6th rank, and then move behind the enemy king to start checking. 1.Rb7 Rg6 [Cutting off the white king] 2.Rb6

 2..Rg4!! [This is important. Heading for the back rank now is premature: 2..Rg1 3.Kc6! when either check fails] 3.d6 [3.Kc6 Rxd4 doesn't help white 4.Rb8+ Ke7 is a theoretical draw as the defending rook is behind the pawn and the king isn't cut off] 3..Rg1! [Now the rook heads for the back rank when there is no useful shelter for white's king]
White can make no progress. 4.Kc6 Rc1+ forces the king to retreat, while 4.Kd5 doesn't require any special treatment, so black could play 4..Rh1 gaining checking distance and waiting for white's king to try to advance. Now, if you look at the position in the first diagram, you'll see a position not unlike this one, a cast iron draw!

Sometimes, the draw is not so easy:
Here, for example, white has advanced the pawn to the brink of promotion, and the threat is Re8+, so black must seek drastic measures. 1.Rh2+ Kg6, and now that the black king is stalemated, 2.Re2!! and black's rook will keep diving in front of its white counterpart!

If the defensive rook is passive, things aren't easy, and maybe even impossible.
Black's rook is passive and white's king has penetrated the 6th rank. 1.Rd6 [Taking control of the 6th rank] 1..Rf8!? [A last attempt]
2.g5! [2.g7? Rf6+!! another stalemate possibility] 2..Ra8 3.g7 Rb8
White has a very simple plan. Rf6-f8, leading to a won pawn ending. 4.Rf6 Ra8 5.Rf8+ Rxf8 6.gxf8=Q+ Kxf8 7.Kh7 and white will promote on 3 moves.

Finally, take a look at this amazing technique!
Black's king is cut off, but the win isn't as straightforward as you'd think. Without the b6 pawn, white would build a bridge on the 5th rank, but that is now not possible. 1.Rd2+ [Driving white's king further from the action] 1..Ke7
[2.Rd5 fails to work after 2..Ra1 3.Kc7 Rc1 and white's king must go back to b8!] 2.Rd6!! [An unbelievable technique!] 2..Rc3 [Taking the rook doesn't help 2..Kxd6 3.Kc8 Rc2 4.Kd8 Rh2 threatening mate, but white promotes with check! 5.b8=Q+]
So what now? 3.Rc6!! [Building a bridge! If the rook isn't taken, then white's king will escape to c7] 3..Rxc6 4.Ka7, and black has no checks and cannot stop promotion!

So that's the theory, what about the example we started with?
I guess we've all been in this sort of position where we're struggling to draw against a much higher rated opponent, who just keeps playing and playing. Hebert changes the structure to try to upset his opponent. 1..f2. White still manages to keep playing solid moves. 2.Ra7 Kg5 3.Rg7+ Kf4 [A repetition is a good sign for the defender] 4.Ra7 Kg4
[My first reaction when I saw this position was to play 5.Ra3 cutting off black's king. 5..f4 and now throw the rook up the board 6.Ra8 when I don't see how black will progress. White played differently, but still good enough to draw] 5.Ra8 [According to Nalimov Tablebase, this position is drawn] 5..f4 6.Ra7 [Again, I like 6.Ra3 cutting off the black king. If 6..f3, white has the stalemate try 7.Rxf3!] 6..Kg3
In this position, after an heroic defence, the game ended. I'm not sure if white ran out of time, but I hope white didn't resign. According to Tablebases there is a move to draw, but only one. 6..Ra3+! [6..Rg7+ 7.Kf3 is hopeless for white] 7.f3 [Retreating the king back to g4 is no winning attempt] 
7..Rxf3+ with the same stalemate  theme! 8.Kxf3 stalemate!

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