Wednesday, February 13, 2013

Fighting methods

I investigated the previous position a bit further (see diagram)

White to move.

Both white and black have a few fighting methods at their disposal with which they can fight for a win or draw. This is an inventorization of the possible fighting methods.
Meaning of the arrows:
Blue = 1st, 4th move
Green = 2nd, 5th move
Yellow = 3rd, 6th move.
Red = moves of the enemy.

White to move.
Despite the wellknown advice to put your rook behind a passer, the rook is much more active on c3 where it puts pressure on c7 and can attack the kingside pawns or assist the defense of the white pawns.

Black to move.
What white wants to do is to bring his king to the black kingside pawns and nibble them away.
With the pawnsac c5, black opens the fourth rank so he can keep the white king at bay with Ra4 while maintaining the pressure against a3.

Black to move.
Blacks king cannot leave c6 because of the push of the c pawn towards promotion.

Black to move.
Black should always be aware of the danger of a rook trade, since that leaves him with a lost pawn ending. So the pawn on c5 is tabu due to the skewer Rc3.

White to move.
White can abondon his queenside pawns as long as he can remove all three black pawns and is left with two connected passers.

White to move.
White must be aware of tricks that leaves him with a sole rook pawn. So he must not play the immediate Rxh5 here, but he must play Ke3 first to avoid the double attack Rf3+
I'm sure there are a few more fighting methods. I will update this post whenever I stumble upon them.


  1. Is sacrificing the c-pawn a good thing to do for black? This is what makes me wonder the most.

    I would know following guidance how to win this ending, but it assumes that sacrificing the c-pawn is not a good strategy.

    So: assuming the c-pawn stays on the board, that makes the a-pawn the guarded passer.
    Because the guidance-rule "the king should block passers and not the rook" it is likely that at some point the black king needs to go for blockading the white a-pawn.
    However, this leads to a loss of activity in the center, and it is very likely that white will win the ending by working with check mate threats against the black king on the a-file.

    The rule with a rook behind pawns is probably wrong understood by you, too:
    It is about the question, wheather white should be in front of his passer of behind of his passer. Because it is in the way of his own pawn, it is better to have your rook behind your pawn. If your rook sits behind your pawn: While you push your pawn forwards this will increase the room for your rook, too.
    If your rook is in front of your pawn: pushing forward your pawn reduces the mobility of your rook.
    That in your discussed position the rook is better on the c-file is clear: first of all: your pawn is guarded by the b2-pawn. And secondly: rook belong on lines. It would be a different story if white had a pawn on c4 and black on b6. Then your c-line isnt half open or open, but closed. Looking then at the position, your rook belongs either on the open d-file, or (if that was not possible) it belongs behind your mobile pawn(s).

  2. Houdini thinks that the pawn sac is a good idea. And indeed the following Ra4 makes life difficult for white. As you will find out if you try to play it out against the computer.

    The rule of the rook behind the passer is ill understood by me indeed since it is partial knowledge and it is only applicable in 5% of the cases sofar. That's why I do these endings, in order to get the rest of the knowledge. As bare rule, it does more harm than good.

    The problem of the black king at the a-file is mainly that black is outnumered on the kingside by the white rook and king.

    Right now I'm able to win this ending against every engine. That was my goal. I learned a lot new patterns. I learned the standard plan for these kind of positions.