Author: Dezhi Zhao
Date: 11:15:21 06/25/04
Go up one level in this thread
On June 25, 2004 at 13:59:51, Uri Blass wrote: >On June 25, 2004 at 13:24:34, Dezhi Zhao wrote: > >>On June 25, 2004 at 12:07:03, Uri Blass wrote: >> >>>On June 25, 2004 at 09:43:43, Dezhi Zhao wrote: >>> >>>>On June 24, 2004 at 20:18:34, Keith Evans wrote: >>>> >>>>>On June 24, 2004 at 15:07:41, Dezhi Zhao wrote: >>>>> >>>>>>On June 24, 2004 at 00:24:39, Keith Evans wrote: >>>>>> >>>>>>>On June 23, 2004 at 13:48:03, Vincent Diepeveen wrote: >>>>>>> >>>>>>>>On June 22, 2004 at 07:46:02, TEERAPONG TOVIRAT wrote: >>>>>>>> >>>>>>>>> >>>>>>>>>Hi, >>>>>>>>> >>>>>>>>>I've never seen any downloadable Chinese chess program that can match >>>>>>>>>a strong human player. IMHO, it's much more difficult to create a master >>>>>>>>>level program than in chess. In chess, when you lose the first pawn,it's >>>>>>>>>likely that you'll lose the game eventually. But, in Chinese chess, you may >>>>>>>>>find yourself in trouble after you have 1-2 pawns up in the opening. >>>>>>>>>And you have to handle many specific endgame positions differently. >>>>>>>> >>>>>>>>>Regards, >>>>>>>>>Teerapong >>>>>>>> >>>>>>>>There is no commercial motivation for writing chinese chess programs that's the >>>>>>>>sole reason why the more popular of the 2 games is dominant in computer games. >>>>>>>> >>>>>>>>I know the rules of both games and can assure you that it is for an outsider >>>>>>>>much harder to write a chessprogram beating the strongest chessprograms, than it >>>>>>>>is to write a chinese chess program beating the strongest chinese chess >>>>>>>>programs. >>>>>>>> >>>>>>>>Note that both require a big effort, but chinese chess is at a much lower level >>>>>>>>thanks to commercial driven developments in chess. >>>>>>> >>>>>>>Don't you think that rules for xiangqi are more complicated that for chess? (See >>>>>>>Chapter 4 Section 4 of http://www.clubxiangqi.com/rules/asiarule.htm) I don't >>>>>>>think that there is any free Xiangqi program which understands these rules. If >>>>>>>you could distill these rules into some trivial C code, then you could help to >>>>>>>improve the computer referees at the online servers, and you could also help to >>>>>>>improve the state of non-commercial Xiangqi software. >>>>>>> >>>>>> >>>>>>Agreed. The rules are so complicated that a restricted search seems to be >>>>>>necessary for an implementation. Chinese rules are even more complicated than >>>>>>Asian rules. >>>>>> >>>>>>>It is my belief that Xiangqi masters could exploit programs which don't >>>>>>>completely understand these rules, but I don't have any firm evidence of this. >>>>>>>It's difficult to find much written by masters which has been translated into >>>>>>>English. It's not clear to me that the rules are well defined in >>>>>>>computer-computer competitions, in fact there are some that believe that the >>>>>>>rules should be simplified for computers. I assume that masters insist on some >>>>>>>official rules when playing computers, but I don't know this for a fact. (Either >>>>>>>AXF or CXA rules?) >>>>>> >>>>>>The effect is more than that you have described. If your program does not >>>>>>understand rules, the search can not produce a correct move in too many cases. >>>>>>I don't see any trend CXA wants to simplify the rules. Instead they tend to make >>>>>>it more complex in each revison. Believe it or not, some Xiangqi masters even >>>>>>admmitted to me that they do not understand the arcane rules well:) >>>>> >>>>>Do you have any examples of really decisive wins by masters over computer >>>>>programs? The shorter the better. >>>>An example come to my mind at this time is a game between my program and a >>>>Hongkong master at ICCS years ago. The program had a wining position, ahead with >>>>materials. However it only knew CXA rules and the game was supposed to be under >>>>Asian rules. The master drew the game by a one-check and one-mate-threat >>>>repetition which is not allowed under Chinese rules. Should the program know >>>>Asian rules, it could have won the game. >>> >>>I see no interest in games when the hard part is to know the rules. >> >>still far from such extent:) >> >>>The hard part should be to choose the correct move and not to find the list of >>>legal moves. >>> >>>I can also define rules that will make it very hard for humans to play the game. >>> >>>For example define a game that is identical to chess except the list of legal >>>moves that is different. >>> >>>Players need to play every time one of the moves that win the most material >>>based on 7 ply brute force search(if there is mate in 4 they have to play the >>>move that lead to the shortest mate and if they can win a pawn by 7 ply >>>conmbination but not more than it they have to play the move that wins a pawn >>>based on 7 ply brute force search). >>> >>>Do not confuse win a pawn based on x ply search with real winning of material >>>and if we play the same game with 1 ply instead 7 plies then every side has to >>>play the biggest capture in 1 ply except cases that the biggest capture >>>generates stalemate and in this case they have to play it if all the alternative >>>leads to position with material disadvantage. >>> >>>Computers can do 7 ply brute force search and find the list of the legal moves >>>but it will be very hard for humans only to find if a move is legal. >>> >>>Uri >> >>I think the major cause of complicated Xiangqi rules is to prevent easy draws. >>Perpetual checks, as for a simple example, is an easy-to-do in Xiangqi even for >>the losing side because a king is confined to only 9 squares. Therefore, >>perpetual checks are illegal. > >I do not think that rule that forbid perpetual check is hard to implement in >software. > Yes. Not fun to implement at all. But it is still doable. >Simply consider every check that force repetition as illegal move. > the one that leads to three fold repetition is illegal or to be verdicted lose by a TD. >Uri
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