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Subject: Re: Christmas Tree Problem

Author: Uri Blass

Date: 00:22:56 12/25/05

Go up one level in this thread


On December 25, 2005 at 03:03:00, Sune Larsson wrote:

>On December 25, 2005 at 02:43:23, John Merlino wrote:
>
>>On December 25, 2005 at 02:32:15, Uri Blass wrote:
>>
>>>On December 25, 2005 at 02:24:19, Sune Larsson wrote:
>>>
>>>>On December 24, 2005 at 20:49:48, John Merlino wrote:
>>>>
>>>>>On December 24, 2005 at 20:30:05, Alessandro Scotti wrote:
>>>>>
>>>>>>On December 24, 2005 at 20:14:19, Mark Ryan wrote:
>>>>>>
>>>>>>>http://www2.forthnet.gr/chess/xmasmil.html
>>>>>>>
>>>>>>>I do NOT know the answer.
>>>>>>
>>>>>>[D]8/3p4/3p4/2pPp3/1pPkPp2/1n1p1n2/P2p2P1/3K4 b - - - -
>>>>>>
>>>>>>Kiwi can't see it either...
>>>>>>
>>>>>> 3/ 9  +7.92  00:00       524  Ng5 axb3 Nxe4
>>>>>> 4/ 4  +7.92  00:00       579  Ng5 axb3 Nxe4 g3
>>>>>> 5/ 5  +9.44  00:00      3290  Ng5 axb3 Nxe4 g3 fxg3
>>>>>> 6/ 7  +9.52  00:00      3998  Ng5 a3 Nxe4
>>>>>> 7/21     M4  00:00    114504  Ng5 g3 Nh3 axb3 Kc3
>>>>>
>>>>>It's a sort of trick question, but there is still a flaw in it.
>>>>>
>>>>>Unless I'm missing something, for it to be a Mate in 2 for Black White's last
>>>>>move had to have been either c2-c4 or e2-e4. After EITHER of these moves, Black
>>>>>capturing en passant leads to a Mate in 2.
>>>>>
>>>>>However, the designation on the page "there is a single answer" is not correct,
>>>>>because White could have made either of those moves, and therefore there are two
>>>>>possible responses by Black.
>>>>>
>>>>>jm
>>>>
>>>>
>>>> I'm not following you here. How, in the name of all Houdinis, could the
>>>> last white move be e2-e4???
>>>>
>>>> /S
>>>
>>>I decided to post the solution after the hint that you give and after
>>>understanding that the site is very old site and there is no point in keeping
>>>the solution as a secret.
>>>
>>>Of course it cannot be e2-e4 because it means that the white bishop at f1 was
>>>not captured by a pawn and the position is illegal because black needs too many
>>>captures to get the pawn structure.
>>>
>>>
>>>Uri
>>
>>Indeed, very impressive.
>>
>>I found a complete description of the solution (although the board is flipped
>>such that it is WHITE to Mate in 2) here:
>>
>>www.gtryfon.demon.co.uk/bcc/news/dec98news.htm#Christmas%20tree%20puzzle!
>>
>>Fun problem!
>>
>>jm
>
>
> Yes, and if you think like children do - you'll see in an instant that e2-e4
> couldn't have been white's last move. If the pawn was on e2 - then Bf1 would
> never ever gotten out. That's why the Houdini hint ;-)
>
> /S

This is still no proof and you need to count number of captures to find that Bf1
could not be captured not by a pawn.

Uri



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