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Subject: Re: Is this solvable by brute force?

Author: Ricardo Gibert

Date: 08:58:32 09/18/03

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On September 18, 2003 at 11:45:39, Ricardo Gibert wrote:

>On September 18, 2003 at 11:25:01, Ricardo Gibert wrote:
>
>>On September 18, 2003 at 10:02:33, Edward Seid wrote:
>>
>>>I'm learning how to program by reading Deitel's Visual Basic.NET How to Program.
>>> I'm eager to try out my new skills on a chess-related project.
>>>
>>>The Pawn Game - as presented by GM Lev Alburt in Comprehensive Chess Course, Vol
>>>1
>>>
>>>[D]8/pppppppp/8/8/8/8/PPPPPPPP/8 w - - 0 0
>>>
>>>The game is won by:
>>>1- capturing all of the opponent's pawns
>>>2- reaching the last rank first
>>>3- 'stalemating' the opponent, while still having at least one move for yourself
>>>
>>>The game is drawn if:
>>>1- both sides' pawns are blocked so that neither side can make any moves
>>>
>>>The programming exercise I've assigned to myself it to try to solve this game
>>>using brute-force minimax.  My question to you... can this game be solved on
>>>today's typical desktop computer using brute-force?
>>>
>>>I've been thinking about this and have made the following observations:
>>>1- while classical chess has a branching factor of around 30, the Pawn Game
>>>branching factor is 16 in the initial position, and around 8 in the
>>>'middlegame', and goes down with each capture.
>>>2- the longest 'game' is certainly less than 81 ply, and is probably around
>>>60-65 (81 ply is calculated by the impossible scenario of each side taking 40
>>>ply each to march all pawns to the 7th rank + 1 ply to promote)
>>
>>
>>Unless I've suffered from a brain fart, a 42 ply game is impossible, while a 41
>>ply game is trivial to construct.
>
>
>Wrong! I'm up to 67 ply being possible.

I miscounted. I can do 66.

>
>
>>
>>
>>>
>>>I'm not planning to use anything fancy like hashtables or board rotation.  I'd
>>>be happy if I'm successful in coding a 10x12 board representation (practice for
>>>writing a classical chess engine in the future), a valid pawn move generator,
>>>and a correct implementation of the minimax algorithm.
>>>
>>>I'm very curious what the solution to this game is.  Is it a win/loss/draw for
>>>White?  Of the 16 possible White moves, which ones win/lose/draw?  How long is
>>>the longest game?  How long is the shortest game?  What is the distribution of
>>>wins amongst the 3 methods of winning?
>>>
>>>Any thoughts or suggestions are appreciated.



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