Author: Vincent Diepeveen
Date: 16:22:19 09/18/03
Go up one level in this thread
On September 18, 2003 at 16:36:09, Andrew Dados wrote: you would be correct wasn't it the case that the rules say that you need 1 additional move left. So both in zugzwang which is easy to get that is defined a draw. That's why i guess outcome is a draw. >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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