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Subject: Re: Piece values in Capablanca's / Gothic Chess

Author: Ed Trice

Date: 06:08:41 01/03/04

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Hello Reinhard,

This is an interesting discussion. I think I have a few examples that might help
explain my perspective.


>please explain, why. Intutivly for me the possibilities of a queen in a 100x100
>board seems to be grown where the pawns will have only a very small profit.

I tend to this of a piece's value to be proportional to the "density" of its
attacking destinations that can be reached compared to the size of the board. As
you add squares to a board, you dilute a piece's strength. As you remove
squares, you increase its strength.

Imagine a Queen on a 6x6 board for example. There are only 36 squares, but when
placed in the center of an open board, the Queen has 5 legal vertical moves, 5
legal horizontal moves, and 10 legal moves diagonally. So, the Queen can control
up to 20/36 = 5/9ths of the board! More than half of the board is acccessible to
the Queen.

On a board that is 100x100, the Queen would have 99 vertical moves, 99
hortizonal moves, and 198 diagonal moves. There are 396 moves total for the
Queen, but there are 10,000 squares! Needless to say, 396/10000 is a small
number.

>May be my method of calculating piece values is simpler than Taylors "safe
>check" method, but I think the Smirf method produces more realistic values
>especially for traditional chess and its pieces:
>
>                8x10              8x8
>Piece       SMIRF  Vortex    SMIRF  Taylor
>--------------------------------------------
>Pawn        1.00   1.00      1.000  1.00
>Knight      3.06   2.50 (!)  3.000  2.50 (?)
>Bishop      3.60   3.00 (!)  3.375  3.03
>King        3.72   ----      3.750  ----
>Rook        5.43   4.75 (!)  5.000  5.67 (?)
>Archbishop  6.65   6.50      6.375  5.53
>Chancellor  8.49   8.25      8.000  8.17
>Queen       9.03   8.75      8.375  8.70 (?)
>

Let's look at another example from the endgame in both the 10x8 board and the
8x8 board. Bishop + Knight vs. King.

If the value of the pieces increase on the 10x8 board, you would expect this to
translate into something like being able to gain some sort of advantage. I
wouldl expect one such metric to be distance to force checkmate in certain
endings.

The opposite is true: winning on the 10x8 board is more difficult.

In 8x8 chess, you can only mate with N + B vs. K on one of two squares: that
being the corner square of the same color as your bishop. While it is possible
to mate with the knight, this mate cannot be forced and requires your opponent
missing a mate in 1 (or maybe 2 at the most.)

In Gothic Chess, on the 10x8 board, I discovered that B + N vs. K can only be
forced on 1 square! That square is the same color of the bishop that is closest
in rank to the enemy king. That is, the square of the same color as the bishop
that is connected to the files (of which there are 10 across) cannot force the
king to be mated. The square which is vertically connected to the ranks (of
which there are 8) can force the mate.

It might even be that for a 10x10 board that Bishop + Knight vs. King is a draw!
Clearly this cannot mean the B and N are "stronger" in this case.

I will compile two differenct version of Gothic Vortex and have them play a
match, if you would like. Let me know which values you want to use, and I will
hook it up.


--Ed



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