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Ultima. Game where each type of piece has a different capturing ability. Also called Baroque. (8x8, Cells: 64) (Recognized!)[All Comments] [Add Comment or Rating]

Greg Strong wrote on Sun, Oct 3, 2004 07:11 PM UTC:

Since you all provided so much input into evaluation, I thought you might
be interested in the various terms I used in the Ultima evaluation
function for ChessV...

I used George Duke's piece values of Pawn = 1000, Withdrawer = 3100,
Coordinator = 2900, Chameleon = 4300, Long Leaper = 5300, and Immobilizer
= 8200.  All immobilized pieces are penalized -25% of their value.  The
Withdrawer gets a small bonus proportional to the value of the most
valuable adjacent enemy piece (provided there is at least 1 square in the
opposite direction for it to move into, although it need not be vacant
presently.)  The Coordinator gets a small bonus proportional to the number
of enemy pieces on the same rank or file as the friendly King.  The
Chameleon gets a couple small bonuses:  for standing adjacent to an enemy
Withdrawer (if there is at least 1 square in the opposite direction to
move into), and when the enemy coordinator is on the same rank or file as
the friendly King.  The Immobilizer gets no bonuses, instead immobilized
pieces are penalized.  The Long Leaper also has no bonuses, but only
because I have no good answers here.  Roberto correctly points out that
the Long Leaper is more valuable if the enemy pieces are not clustered,
and not on the edge, but I cannot think of a way to determine that without
spending far too much CPU time.  I will continue to think about it.

Also, in the opening, pieces are given a bonus for the first move
(development), a small penalty for moving twice, and a large penalty for
moving the same piece three or more times.  These adjustments are slowly
scaled down as the game progresses into the middle-game.