Friday, June 20, 2014

Rook Endings 4: Rook Versus Two Isolated Pawns.

We considered the fascinated case of rook versus two connected pawns in the previous post in our rook endgame series. This time the focus is on the rook versus two isolated pawns ending. Let's get right to it.

Second Case: Rook Versus Two Isolated Pawns.

In most rook versus two isolated pawn positions the side with the pawns is defending. The further separated the pawns the more difficult it is for the player with the pawns. This is illustrated clearly by the fact that pawns separated by four or more files can't defeat a rook on the 8th rank.

Fig 1. White to Move and Draw!

Here black is threatening Kc2, to prevent this white must play 1.Rg1. If 1...Kc2 then 2.Rxg2+ Kc1 and 3. Rxb2 draw. If after 1...Ke3 then 2.Rb1 and white draws using the same method.

By contrast, in the following position white loses. In this case if 1.Rf1 to escape 1...Kc2, black plays 1...Ke2 and wins.

Fig 2. White to Move and Lose!

If he knew the drawing method discussed above, white should have been able to draw in the following position that appeared in 2013 in Andreas Walter (2028) - Michael Topp (1978) 0-1

Fig 3. White to Move and Draw!

The simplest way to draw would be to play 1.Rg1, after which he can take the g pawn if black does not play 1...a2. If 1...a2 then white draws as per the analysis of fig 1. Instead, white tried to take the a pawn with the king and the game continued 1.Kd6 Ke3 2.Kc5? (2.Ra1 still draws) Kf2 3.Kb4 a2! (white must have missed this nuance or thought there was no better line) 4.Rb2+ Ke3 5.Rxa2 g1=Q. White lost the rook versus queen endgame.

As John Nunn says in Nunn's Chess Endings, vol 2 (2010), most rook versus two isolated pawn endings should actually be played as if they were rook versus lone pawn endings, which means that the player with the pawns needs to focus on drawing with the stronger of his pawns. The player with the rook, by contrast, must avoid being distracted by the weaker pawn. There are cases where this general rule is not true--and they are the more difficult ones to play--but otherwise these ideas are important to keep in mind.

A good example illustrating Nunn's point is the following position discussed in Muller and Lamprecht, Fundamental Chess Endings (2001), which is from the 1995 game J. Piket - V. Salov

Fig 4. White to Move and Draw!

White secures the draw by ignoring his f pawn. 1.Kg4 Rc1 2.h5 Kb3 3.h6 Kc4 4.Kf5 Kd5 5.h7 Rh1 6.Kg6 Ke6 7.Kg7 Rg1+ 8.Kf8 draw. It is instructive to see what would have happened if white had thrown in f4, a losing move. If, for example, 7.f4 we reach the following position:

Fig 5. Black to Move and Win!

Here black ignores the f pawn, playing 7...Ke7 and stopping white's Kf8 drawing line in the main variation. (It should be noted that 7...Rg1+ also wins.) If 8.Kg7 then 8...Rg1+ 9.Kh6 Kf7 10.h8=N+ Kf6, and we reach a position we have already studied that is winning for black. On it see the discussion of the Thornhallsson - Sadler game in our analysis of the Rook versus two connected pawns ending. If 8.f5, black wins with 8...Kf8 stopping both ...Kg7 and an eventual f8. For a board with these lines go here.

The following example from a 2013 rapid game Evgeny Postny (2631) - Romain Edouard (2657) 1-0 also illustrates Nunn's point well.

Fig 6. Black to Move and Draw! 

Here black played 1…e4? After 2.Kd4 Kg4 3.Ke3 Kg3 4.Ra8 h3 5.Rg8+ Kh2 6.Kxe4 Kh1 7.Kf3, we reach a position we studied in our rook versus pawn analysis that is winning for white. By contrast, 1…Kg4 draws whether white attacks with his rook on a rank or on a file. After 1…Kg4 2.Ke4 h3 3.Ra8 h2 4.Rh8 Kg2 white will have to trade his rook for the pawn or accept a repetition of moves. And, after 1…Kg4 2.Ra4+ Kg3 3.Kxe5 h3 4.Ra3+ Kg2 5.Kf4 h2 6.Ra2+ Kh3 the game is a clear draw.

The most difficult positions are those in which the draw requires play with both pawns, as in the following position, which I take from Nunn's Chess Endings, vol 2 (2010) and appeared in Ermeni - Cetkovic in 1991.

Fig 7. Black to Play and Make White's Life Difficult!

Here black played 1...Rb1, and after 2.Ka6 Kg3 3.e5 Kf4 4.e6 Ke5 5.e7 Rb8, white should have played 7.Ka7 Re8 8.Kb6 Rxe7 9.a6 and black will have to trade his rook for the pawn. Instead white played 7.e8=Q Rxe8 8. Kb7 Kc5 9.a6 Re7+ and white resigned.

It is occasionally possible for the side with the pawns to win as in the following position, which is from the 2000 game between Bart Timmermans - Martijn De Clerck 0-1.

Fig 8. White to move and Lose!

Here white checked from the side and after 1.Rg2+ Kg3 2.Rb1 f3 3.Kd5 f2 4.Ke4 Kg2 and white resigned. It would have been more challenging for white to play 1.Rg8+ Kh1 2.Rf8 f3 3.Rxf3 Kg2 and black will queen, but have to win the queen versus rook endgame. Or, even better white could try 1.Rg8+ Kh1 2.Kd5 f3 3.Rf8 Kg2 4.Rg8+ Kf2 5.Rh8 Kg3 6.Rg8+, Kf4 7.Rf8+ Kg5 etc. with the idea of making it to the seventh rank and stopping white's checks and then queening one of the two pawns. For the full analysis follow the game link above.

If black's f pawn is one square back on f5 instead of f4, then the game is a draw. This is illustrated by the 2001 game Edwin A. Spencer - Richard Wiltshire (2120) 0.5-0.5 in which the following position was reached.

Fig 9. Black to Move and Win!

Here black threw away the win with 1...Kg4, a reasonable move if he thought that he only had drawing chances. If 1...Kg4, the correct drawing technique here is to play solely with the rook, which works because the pawns can't protect each other. After 2.Rc7 h2 3.Rh7 Kg3 4.Rg7+ Kf2 5.Rh7 Kg1 6.Rg7+ and black can't make progress. Now, if black had played 1...f4 he would have won following 2.Rc7 f3 3.Rg7+ Kf4  4.Rf7+ Kg3 5.Rg7+ Kf2 6.Rh7 Kg2 7.Rg7+ Kf1 8.Rh7 f2 9.Rxh3 Kg2 and black will queen.

Looking at these last two positions, I think we can deduce the following rule: two isolated pawns separated by one file win when both are protected by the king if the opposing king is unable to help the rook and the sum of the pawns' ranks is six or less when the rook begins checking from behind. Thus a pawn on the 4th and another on the 2nd or two pawns on the 3rd rank win.

What if the pawns are separated by two files? In the case of two files of separation, the pawns can only win if they are both on the third rank or closer to queening. With them both on the third rank, the win depends on how far away the rook's king is and how much checking distance the rook has. In the following position, for example, the side with the pawns is winning. The winning technique is instructive.

Fig 10. White to Move. How does Black Win?

Here black first needs to walk his king towards the rook to stop the checks. 1.Rg7+ Kf3 2.Rf7+ Kg4 (If 2...Ke2? then 3.Rh7 draws.) 3.Rg7+ Kf5 4.Rf7+ Kg6 5.Rf1 (The rook tries to defend from the other side of the board.) e2 6.Re1 h2 8.Kb7 Kf5 (The king begins his march back to the pawns.) 9.Kc6 Kf4 10.Kd5 Kf3 11.Kd4 Kf2 12.Rh1 e1=Q 13. Rxh2+ and black should win the queen versus rook endgame.

If White has another rank of checking distance, he draws because he has a tempo more than in the above example.

Fig 11. White to Move and Draw!

I will not give the moves for this so that you can try to visualize the draw to its end.

In sum: what should we remember about rook versus two isolated pawn positions:
  1. They should often be played like rook versus lone pawn positions.
  2. The side with the rook can secure a draw without its king's help by checking from behind when the pawns are not too far advanced.
  3. Our rule about when two isolated pawns separated by a file win: when protected by the king if the opposing king is unable to help the rook and the sum of the pawns' ranks is six or less when the rook begins checking from behind.
  4. As with most simple rook endings, although these positions appear to be straight forward, they can be very difficult to play.
NEXT UP IN OUR ROOK ENDING SERIES: ROOK VERSUS QUEEN AND ROOK VERSUS KNIGHT (NO PAWNS). Why? Our analysis has regularly stopped with the theoretical rook versus queen ending--which should be a win for the queen--and the rook versus knight ending--which should be a draw, but these endings are not so simple. We need to learn how to play them.

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