Author: Don Dailey
Date: 15:44:13 12/08/97
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On December 08, 1997 at 17:10:06, Machiel de Heer wrote: > >On December 07, 1997 at 22:20:22, Don Dailey wrote: > >>>>Could you tell me what is the maximum number of legal moves in a >>>>chess game position? >>>>A) In theory? >>>>B) In practice? >> >> >>>3r2k1/1p3ppp/p4P2/P3r3/1P3nPP/5RQ1/2q5/R6K b - - ; 65 legal moves. >> >>>>Q6Q/4Q3/1Q6/5Q2/2Q5/R5Q1/3Q2NN/1R3KBk w - - ; 195 moves. >> >> >>Here is an 82 move one found in the search from a normal position: >> >> 1r1Q3r/5k1p/B3b1N1/2p1QN2/4p3/8/1PP3KP/R3R3 w - - ; 82 legal moves >> >>But I noticed there were 2 queens on the board. White had 2 queens, >>2 mobile rooks a mobile bishop and even the king had 7 sqaures it >>could move to. Both knights were pretty mobile and there were 3 pawns >>each on the board. The position looked natural, not like a >>construction. >>Since a lot of pieces were close to maximum mobility it would be hard >>for me to believe a 100 move position even exists with only 1 queen on >>the board. >> >>If each piece had maximum mobility and no multiple pieces were allowed >>unless they existed from the opening position: >> >>27 queen >> 8 knight >> 8 knight >>13 bishop >>13 bishop >>14 rook >>14 rook >> 8 king >>--------- >>105 moves. >> >>The pawns could add moves but it's hard to believe they >>would not interfere with the range of other pieces. Also it's hard >>to believe the pieces themselves would not interfere with each other. >> >>I believe it will be truly difficult if not impossible to find a >>position >>with 100 legal moves possible assuming only up to 1 queen and 2 of >>everything >>else. With multiple queens we see it's quite possible to exceed 200 >>moves. >> >>-- Don > >Hi Don, > >I've played a bit with the "1 queen, 2 of everything else"-problem >(pawns excluded). Initially i could only get to 99, but: > >4k3/8/4N3/4B3/2N1B1K1/1R7/5Q2/3R4 w - - ; 100 legal moves > >Hope i didn't miscount. My program wouldn't accept it. >Seems to be the maximum, since the Queen + 2 Bishops can only get to 49 >(out of a possible 53), after which there isn't enough space left for >the knights (giving up one square). Can't prove it though :-) > >-- Machiel Hi Machiel, I count 100 legal moves too. I assumed you meant /1R6/ instead of /1R7/ in your fen position. I'm surprised you got up to 100! Good job! Perhaps a move or two extra can be squeezed? Did you try maximizing the queens mobility? By the way, why no pawns? I was not excluding pawns in my definition. I see that a few pawns could be added to bump this up a few moves. Don
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