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Ideal Values and Practical Values (part 3). More on the value of Chess pieces.[All Comments] [Add Comment or Rating]

Robert Shimmin wrote on Sun, Jul 13, 2003 03:44 AM UTC:

For anyone who was curious about my previous prediction that an amazon may
be a full rook more powerful than the queen, I ran the following
experiment.  Whether it means anything is up to you to decide.

I ran scripted Zillions to play against itself for 500 games where
black's queen was promoted to amazon, but black was missing its queenside
rook.  At strength 4, results were 249-62-189, or 85 ratings points in
white's favor.  At strength 5, results were 265-57-178, or about 110
ratings points.

For comparison, samples of 1000 games each found pawn-and-move to be a
135-point advantage at strength 4 and a 260-point advantage at strength 5,
while giving white two opening tempi instead of one is a 50 point
advantage at strength 4 and a 140-point advantage a strength 5.

Based on this, I would guess that the amazon falls short of being a full
rook stronger than the queen by perhaps half a pawn, but that still leaves
the amazon a pawn stronger than a queen and a knight.