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        riddles >> medium >> Reconstruct Chess Game (I)
        
(Message started by: THUDandBLUNDER on Oct 9^th, 2003, 9:38am)

Title: Reconstruct Chess Game (I)
Post by THUDandBLUNDER on Oct 9^th, 2003, 9:38am

White and Black each played 7 moves and arrived at the position below. What were the moves?

Title: Re: Reconstruct Chess Game (I)
Post by Barukh on Oct 12^th, 2003, 11:19am

[smiley=blacksquare.gif][hide]
1. b4 h5
2. b5 h4
3. b6 h3
4. bc hg
5. cbQ! R:h2!
6. Qb8:h2 ghR
7. Qh2-h8 R:h8
[smiley=blacksquare.gif][/hide]

Awesome problem! I wonder where do you get them from, THUDandBLUNDER?

And yes, thank you and Lightboxes for the appreciation in Reconstruct Chess Game (II).

Title: Re: Reconstruct Chess Game (I)
Post by Lightboxes on Oct 12^th, 2003, 11:08pm

ARGHHHHHHHHHHHHHHHH....!!!!!!!!!!!!!
Unbelievable!!!
I thought of those [hide]two promotions [/hide]BUT in seperate cases and didn't put them together! WHAAAAA...I want my bottle :'(

You make it sound so easy Barukh
Please post at least two sentences of how you analyzed the situation so the members of this forum can learn versus um...not learn.

I'll do the same because I know I posted a few answers without an explanation to how I got there.

Title: Re: Reconstruct Chess Game (I)
Post by Barukh on Oct 13^th, 2003, 7:41am

on 10/12/03 at 23:08:10, Lightboxes wrote:

You make it sound so easy Barukh
Please post at least two sentences of how you analyzed the situation so the members of this forum can learn versus um...not learn.

By no means it was easy! If you knew how many times I was on the edge to give up...

Regarding my analysis - it's not easy to systematically describe the thinking process, but I'll try. Since other members may still want to think about the solution, I'll make it invisible.

[hide]I started by analysing what pieces may capture the missing pieces. It was obvious that 2 pawns may capture 2 pawns, and then I concentrated on white Bishop b1, and black Rook h8. However, there were too many moves, to get to the position. Then I realized that the black Knight b8 may be of some help by capturing the white pawn at b4. Quite quickly, I arrived at the following 8-move "solution":

1. b4 c5 2. g4 h5 3. Ca3 Nc6 4. gh N:b4 5. C:b4 R:h5 6. C:c5 R:h2 7. Ca3 R:h1 8. Ca1 Rh8.

Here, I got stuck. Besides, I had a feeling that this line cannot lead to a solution, because I felt that the solution must be unique even in the order of the moves, and that was not the case with the aforementioned solution.

Then, it came the moment when I recalled seeing chess reconstruction problems where missing pieces were (unexpectedly) captured at their initial positions - and here arose the idea of pawn promotion. I saw that the white pawn may eat two pieces in just 5 moves! The promotion of the black pawn came instantly.

Then, I ran into another problem: I thought that the promoted white pawn must die at h2. It seemed then there are too few moves for white ( 6 ), and too many for black ( 8 )... It took me another minute or two to realize that the Rook h8 may be the promoted rook! And then all the pieces fit together.

It turned out that I was right about the uniqueness of the solution...
[/hide]

Title: Re: Reconstruct Chess Game (I)
Post by THUDandBLUNDER on Oct 13^th, 2003, 9:01am

Excellent analysis, Barukh. If you and Lightboxes like these sorts of puzzles I will post some more (although the general level of interest seems to be low).

Quote:

Awesome problem! I wonder where do you get them from, THUDandBLUNDER?

If I told you, I would have to kill you! ;D