V. Reinhart wrote on Thu, Jul 20, 2017 02:16 AM UTC:
Joe Joyce (and others interested):
Here's the details of my tests to estimate the value of a guard. Using Fairy-Max, I set up games on a 10x8 board. Pieces on each side placed as: RXNBQKBNXR.
X represents a variable piece, which was always different between black and white.
For example, black might have X = two knights and white has X = two guards (or vice-versa). Then I ran games (engine vs. engine with long time control) and kept track of scores. In all cases the armies were switched (W/B) so that half the games were each way. (scores are based on win = 1, draw = 0.5, loss = 0).
First, one problem in setting up a test is that Fairy-Max requires all pieces to have an assigned value, and going into a test the assigned value of a guard is unknown.
The first approximatelly 200 games were to "hunt" for the guard's best assigned value. I found guards play best with an assigned value between 300 and 375. Within this range games were not sensitive to their assigned value. But if the assigned value is lower (tested 250) or higher (tested 400) then guards don't help their side to play well (and these results are discarded from the final summary).
An Overall Summary of only games where guards have this "optimal" assigned value (300, 350, or 375):
Joe Joyce (and others interested):
Here's the details of my tests to estimate the value of a guard. Using Fairy-Max, I set up games on a 10x8 board. Pieces on each side placed as: RXNBQKBNXR.
X represents a variable piece, which was always different between black and white.
For example, black might have X = two knights and white has X = two guards (or vice-versa). Then I ran games (engine vs. engine with long time control) and kept track of scores. In all cases the armies were switched (W/B) so that half the games were each way. (scores are based on win = 1, draw = 0.5, loss = 0).
First, one problem in setting up a test is that Fairy-Max requires all pieces to have an assigned value, and going into a test the assigned value of a guard is unknown.
The first approximatelly 200 games were to "hunt" for the guard's best assigned value. I found guards play best with an assigned value between 300 and 375. Within this range games were not sensitive to their assigned value. But if the assigned value is lower (tested 250) or higher (tested 400) then guards don't help their side to play well (and these results are discarded from the final summary).
An Overall Summary of only games where guards have this "optimal" assigned value (300, 350, or 375):
asymmetry: [2 guards vs. 2 bishops]
guards win (score) = 40/80 = 50.0%
asymmetry: [2 guards vs. 2 knights]
guards win (score) = 46/80 = 57.5%
asymmetry: [2 guards vs. 1 bishop and 1 knight]
guards win (score) = 101/200 = 50.5%
Conclusion (on a 10x8 board, with other FIDE chess pieces):
A guard's value is:
1) equal to a bishop.
2) slightly superior to a knight.
If any questions or comments feel free to leave a message.