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Combination Challenge #68

This one is a bit more involved than the last one.

This, like the last one, is from chapter 2 of Combination Challenge. The tactical motif is the pin. You have to either make use of the pin, or break a pin.

image
Black to move

Graphics courtesy of Exachess

I’m gonna call this one for KGrupa, who at least came up with the correct plan and ending.

1. … Kh7!
2. Be1 Kh6
3. Bc3 Kh5
4. Be1 Kg4
5. Bc3 hxg2+
6. Rxg2 Kh3
7. Be1 Bxg2#



Posted by Christopher    United States   on 02/04/2013 at 10:10 PM   
 
  1. Whats a Pin?

    Posted by Rich K    United States   02/05/2013  at  05:14 PM  
  2. Rick --- A pinned piece is one that cannot move because to do so will cause the king to be put into mate or it will lead to a loss of material with no compensation.

    I do not see anything great here but for white the king side of the board is locked and any move will cost him material. A rook move leads to mate.

    Black has threats on the Rook and Knight pawn.  He also has time on his side. For now I would delay my attack on the king side and move the black king towards the center and start to get him in the game. So.

    1. ... K-f8 I will see what black does before deciding whether to take the rook or continue to centralize likely aiming for the white queen side pawns and an eventual win by pawn promotion.

    This should be enough for the win but now that I have made my move and my clock is no longer running I will look for something better.

    Posted by Wes    United States   02/05/2013  at  06:58 PM  
  3. Right piece Wes. Wrong square.

    Posted by Christopher    United States   02/05/2013  at  07:09 PM  
  4. Everything is pretty well locked up.
    The Pawn at F4 impedes the progress of Black’s Knight Pawn, and must be eliminated.
    So, G8-H7 gets the Black King moving in that direction.
    White can’t prevent the loss of the Pawn.

    Posted by Samoore    United States   02/06/2013  at  08:11 AM  
  5. A pawn? White is about to lose at least 3 pawns. White has no useful move for several turns anyway. He can either wobble his bishop back and forth just burning time, or he can move one of three pawns into a sacrificial position. Black can move Bxf4 with impunity; White can not counter: to move the rook is to invite mate, Bd2 is an immediate sacrifice and Bd4 will cost him his pawn at b4 in 2 turns. So instead of a quick end we’re going to see about 8 turns worth of pawn killing with Black only losing the B6 or A6 pawn maybe, and the corner pin will not have changed an iota.

    White can not win and should surrender, or else face being nibbled to death by ducks.

    Posted by Drew458    United States   02/06/2013  at  10:12 AM  
  6. Three pawns? White gets mated in 7!

    Posted by Christopher    United States   02/06/2013  at  10:25 AM  
  7. According to Rykba, chewing on the problem for twenty-five minutes and looking at over 968,000,000 positions, with the proper white move, which is Samoore’s K-h7, it is mate in 21!

    My move k-f8 was not nearly as good.  It would have taken 28 moves or so.  My only excuse for missing the best move is that I got a phone call when analyzing move 643,700,000 and lost my train of thought.

    Posted by Wes    United States   02/06/2013  at  02:01 PM  
  8. I meant to say the move proper black move k-h7 of course.  One thing quite interestion about this position is on the queen side.  If white can hold a pawn on b5 and keep his e pawn in place, a draw is not out of the question.  Black has to get his king into play or it could get stuck on his own side of the board.

    Posted by Wes    United States   02/06/2013  at  02:22 PM  
  9. OK, this is what I see:

    Black moves his King down to g4. Then hxg2, R recaptures, Kh3, and BxR mate. One other preliminary move might be necessary: ... b5, to get all black pawns on white squares. I don’t see any useful counterplay for White.

    Posted by KGrupa    United States   02/07/2013  at  04:08 PM  
  10. KGrupa got this one. Don’t see any need for … b5 though.

    Posted by Christopher    United States   02/07/2013  at  06:09 PM  
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