Friday, February 24, 2017

Another hole

When you come close to the endgame, the rules of chess seem to change. I don't know what causes that feeling. While the amount of pieces diminishes, the amount of space increases. The net result being that the amount of possibilities doesn't become lesser when you near the endgame. Only the nature of the possibilities changes.

The diagram below is a type of position that is continuously spilling my rating points due to my talent to find the wrong squares. Let's see if we can expel some calculation by logical pondering.

Diagram 1. Black to move

6r1/1p1b3p/3P4/2P2k1P/1P2p2K/5B2/5P2/4R3 b - - 0 1
[solution]

The last move of white was 1. Bxf3, taking a pawn.

Feel free to comment already. That makes it easier for me to get to the essence of the position, since you guys think differently.

Update

After 2.exf3 Re7 we reach the position that gives the most problems. How to judge it? Materially, black has a bishop for two pawns.

Let's have a look at the critical position.
Diagram 2. The critical position. Black to move
If you want to force the game in your direction, it doesn't make sense to chase a mobile piece. The white rook for instance is very agile. What is white's most immobile piece? Definitely his king. It has no duties to perform, no functions that is, but due to being sandwiched between the rim and the rook, it suffers lack of space. In fact, if black was allowed to move three times in a row, Rg1, Kf4 and Rh1# he would mate the white king. Since it is blacks turn, he comes up short two tempi. For the mate it is necessary that the black king can remain on the f-file, and go to f4 in due time. The move Be6 is designed to prevent the white rook to hinder the black king. If white follows up with a normal looking move like 3. ... Le6 4. Rxh7 or 3. ... Le6 4. Rxb7, he gets mated. To abandon immediate disaster, white must deflect the black pieces by sacrificing his main asset, his protected passed pawn. 3. ... Le6 4.d7
 
Diagram 3. Black to move

After 4. ... Rg4+ 5.Kh3 Rd4 black can pick up the passed pawn in due time. When white is robbed of his protected passed pawn, blacks extra bishop starts to count. When the rooks are traded, it is over. As you see, it wasn't necessary to keep the criminal behind lock and key. Mere police surveillance was enough. Due to the mate threat.

7 comments:

  1. Meterial: Black is down 2 Pawns
    Tactical weaknesses: More or less everything ( thats the problem with endgame tactics )
    Whats the problem about? Promotion? CheckMate? Material? : Material

    So:
    ... e4xBf3
    Re7

    Its a defensive puzzle now , i was thinking for ~3 minutes
    The Bishop and h7 ( and b7 )is hanging
    There is some threat of pawnpromotion ( d6-d8 or h5-h8 )
    Now i did start calculating lines beginning with active defenses besed on the weak white king like

    ... Kf4
    Rf7+ Bf4

    ... Rg1
    RxBd7 Rh1 but not checkmate

    But i was not able to make such ideas work
    I did learn during my search for an idea that f7 is critical so my instinct told me it has to be Be6. The move saves the bishop and increases the preassure to the white king

    ReplyDelete
  2. Wow! I have finally found it! What a awekening shot! :). This example shows how much is my chess mind filled with false (harmful) rules!

    I am really curious how often sees this position and what are (were) their chess thinking process!

    ReplyDelete
  3. At first I started to analyze the position "as an endgame". I.e., I looked at the underlying pawn ending. What if there are no pieces on the board? What if the b-pawns were traded? What if there are pieces but the rooks are traded?

    I had already written 4 pages with 3 diagrams when I decided to throw it all in the metaphorical shredder and to start over again. Now I let me be guided by the immobility of the pieces. Rook? Too volatile. Pawn phalanx? Too mobile. Pawn h5? Can be blocked but takes too much time. Pawn f2? Completely blocked. Good target, but it takes 5 moves to get the full reward, i.e. the promotion of my f3 pawn. (Ignoring counter play). Remains the white king. Already in the cage, and mated in 3 moves, counter play not counted. This kind of pondering gives a clear idea of where to focus your attention. All pondering can be done without any serious calculation.

    Then you know which moves you want to make. The question now is: what is necessary to make these 3 moves possible? That will lead you to the necessity to protect f7. Since you have a bishop to save, Be6 is the logical move.

    ReplyDelete
  4. Ignoring counter play. That is a means to look into the future without calculation. Just like looking at the LoA (Line of Attack) without being bothered by the blocking pieces in between.

    Chess moves comes in pairs. If my opponent hinders me with one move, I usually need one move to circumvent that.

    Say, I have, in a different game, entombed a bishop. It is immobile due to lack of space. Your line is only one move long: take the bishop. Now your opponent can throw all kinds of threats at your head which you have to dodge. But in the end, when he has run out of objects he can throw at you, you will eat the bishop. (You are a vulture, remember?)

    ReplyDelete
  5. Ignoring counter play. Only something that is immobile will wait for you at the end of the line. Only wildlife that has been hit will wait for the vulture.

    ReplyDelete