Author: Andrew Dados
Date: 13:36:09 09/18/03
Go up one level in this thread
On September 18, 2003 at 10:27:33, Vincent Diepeveen wrote: >On September 18, 2003 at 10:02:33, Edward Seid wrote: > >A very illusional game thanks to the rules. Trivially with the normal chess >rules this is a much easier game to keep a draw than without :) > >If white goes e4, then black answers e5. >If white goes a3 then black goes a6 in principle. > >In short the only option white has is to start with a pawn to the 3d rank one >day. > >Instead very clever pruning methods involving a passer that's unstoppable and >further than any pawn of the opponent, will reduce search space significantly. > >A good winning attempt for white is illustrated by a well known trick where 3 >pawns at a4,b4,c4 win always from pawns at a6 b6 c6 as you can create a passer. > >So that is the only trick white can go for. > >Starting with for example 1.a4,a5 2.c3,c6 3.b4 > >now white can capture on a5 winning a move and after winning that move it can >win another tempo by playing a6 bxa6 a5!, but black cannot play b5 creating >symmetry. > >So i would go 3..b6 there > >Now c4 is never possible as you after axb4 can already evaluate that as a loss >for white. > >b5 is never possible for white and bxa6 doesn't solve a thing forever. > >4.d4 is answerred by d5. > >So playing for semi-symmetry for black is already very effective. > >So the first guess that this would be a simple draw for black is not exactly >true, but at second glance a few simple rules will produce great killermoves for >black. > >A good evaluation function and move ordering can do miracles in this game to >find out it is a draw. After a few moves like that white will get in zugzwang and black wins. Remember - no King in this game. -Andrew- > >>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) >> >>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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