I signed off the post on Engine Evaluation just as I was getting ready to put up the Christmas tree. The tree went up, came down just after the new year started, and is now in a compost heap somewhere. As for IM Kaufman's article 'The Evaluation of Material Imbalances', which I linked in the 'Engine' post, he identifies four types of material imbalance:-
- Unmatched minor pieces
- Minor piece vs. three Pawns
- Rook vs. minor piece (the exchange)
- Queen vs. pieces (without Queen)
Using his database analyses of these imbalances, he assigns the following values to the pieces.
- 1.00 - P
- 3.25 - B/N plus 0.50 for the Bishop pair
- 5.00 - R
- 9.75 - Q
These values are subject to modification based on other pieces still on the board. For example, the advantage of the exchange is higher for the Rook if there are no other major pieces on the board.
His values are particularly important because they are used in engine evaluations. Rybka is one example.