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Title: White to Play and Win III Post by THUDandBLUNDER on Dec 31st, 2003, 1:01am This is a standard type chess puzzle. |
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Title: Re: White to Play and Win III Post by Margit on Dec 31st, 2003, 2:00am Well, it's fairly obvious that the black bishop is locked on the H2-B8 line otherwise it's game over. Likewise the white king is locked on it's square. So, what to do ? Well a winning position can be achieved if we get the the white bishop to the [HIDE] B8 [/HIDE] square. So we move the white bishop to one of [HIDE]E7, F6, G5, H4 squares and then onto the G1-A7 line and the black king cannot stop it.[/HIDE] |
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Title: Re: White to Play and Win III Post by THUDandBLUNDER on Dec 31st, 2003, 2:53am Quote:
Right idea, but 1. Be7 won't work. So we have 1. Bg5 (say) Kb6 2. Be3+ Ka6 Now what? |
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Title: Re: White to Play and Win III Post by Margit on Dec 31st, 2003, 3:13am Yep, E7 is bad. Now what ? - Simple B-D4. Black can now only move A5 or B5 - mission accomplished. |
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Title: Re: White to Play and Win III Post by THUDandBLUNDER on Dec 31st, 2003, 4:05am on 12/31/03 at 03:13:30, Margit wrote:
What's wrong with a bishop move? |
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Title: Re: White to Play and Win III Post by Margit on Dec 31st, 2003, 4:30am Yep, indeed, must have cucumbers in my eyes. Hmm intriguing. |
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Title: Re: White to Play and Win III Post by James Fingas on Dec 31st, 2003, 7:43am Here is my contribution. It's not a complete solution yet. As Margit pointed out, the black bishop is confined to its diagonal. White wins if he can trade bishops. Therefore white can win if he can get the white bishop onto B8 or C7 without the black king attacking it. To get onto C7, the white bishop can start at either D8 or A5. To get onto B8, the black bishop must be on A7. To get to A7, the black bishop can be anywhere along tghe A7-G1 diagonal. Therefore, the black king is confined to the square C6 when the white bishop is on D8 or A5, and the black king is confined to A6 when the white bishop is on the A7-G1 diagonal. A few more interesting points: if the white bishop is not on D8 or A5, but is on one of the diagonals D8-H4 or A5-E1, then the black king in general must be on B6 or B5. That is because the white bishop can attack either A7 or C7 in one move, so the black king has to be able to defend them in one move. If the white bishop attacks the black bishop from a diagonal other than B8-H2, then the black bishop must move out of the line of fire. Otherwise, white can have a bishop trade for a win. The white king is relatively immobile, only being able to move if the black king can be forced on to B5. But it looks like if white can force the black king on to B5, then he can win by other means anyways. But keep the possibility of white moving the king in mind, anyways. My final observation is that if white's first move is B-A5, then black's response must be B-D6. Otherwise, white's bishop can move along the A5-E1 diagonal to attack the black bishop, gaining a move on black and allowing white to move on to the A7-G1 diagonal to attack A7 without black having a response. |
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Title: Re: White to Play and Win III Post by Margit on Dec 31st, 2003, 8:31am "My final observation is that if white's first move is B-A5, then black's response must be B-D6." James, I don't agree. Black must move b5 or b6, otherwise white plays B-f2 and it's curtaiins. |
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Title: Re: White to Play and Win III Post by THUDandBLUNDER on Dec 31st, 2003, 10:21am Quote:
Margit, I think you are confusing two possible first moves by White. Here White has played Ba5, not Bh4. Hence Ba5-Bf2 is not possible. (James' obserbvations are correct.) |
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Title: Re: White to Play and Win III Post by Margit on Dec 31st, 2003, 11:06am Yes h4 definitely not = a5. Gee. Is this at all possible TB ? As long a WB is sitting on the g1-a7 diagonal, the BK sits at a6, but as soon as WB moves off, WK moves to B6. You can gain a tempo move by sitting behing the BB forcing it to move, but that doesn't appear to help. |
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Title: Re: White to Play and Win III Post by THUDandBLUNDER on Dec 31st, 2003, 10:06pm 1. Ba5 is actually refuted by Bd6. So that is not White's first move. We have 1. Bh4 (or Bg5 or Bf6) Kb6 2. Be3+ Ka6 Now what? |
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Title: Re: White to Play and Win III Post by Margit on Jan 1st, 2004, 7:27am OK Here goes B-c5 (have to prevent BB moving d6) BB moves to one of g3, f4, e5 B-e7 K-b6 (or b5) forced B-d8 K-c6 (forced) And now white moves his bishop behind the black bishop at f6, g5, h4 depending where the BB is. Curtains, black moves bishop and white is on the g1-a7 diagonal. |
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Title: Re: White to Play and Win III Post by THUDandBLUNDER on Jan 1st, 2004, 9:24am That's it, Margit. I think you noticed the rather subtle point that White cannot play any old waiting move on move 3. eg. 3. Bd4? Bd6! 4. Bf6 Kb6 5. Bd8+ Kc6 6. Be7 Bh2 and White cannot gain access to the g1-a7 diagonal because c5 is controlled by the Black king. |
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Title: Re: White to Play and Win III Post by Margit on Jan 2nd, 2004, 1:17am I'm wondering what happens if the black bishop is at d6 instead of h2 in the initial position. 1. Bh4 Kb6 2. Be3+ Ka6 Now we have to make a waiting move 3. Bd4 Bh2 Note black's move is forced as anywhere else is like the original problem. 4. B-f6 K-b6 5. B-d8 K-c6 And now we have recreated the original position which can be solved as in previous post. Have I missed anyting TB ? |
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Title: Re: White to Play and Win III Post by THUDandBLUNDER on Jan 2nd, 2004, 3:30am Quote:
I think it is simpler. With the Black bishop on d6 to begin with, White can just attack it immediately with 1. Be7 eg. 1. Be7 Bh2 2. Bh4 as before If the Black bishop doesn't go to h2 White just attacks it again. The original position is checkmate in about 25 moves against best play. |
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