The a does not stand for 'after' but for 'and again', which is the same as 'before'. So afsW means W before fsW: first a W step in any of the 4 directions, and then another step at 45 degrees (fs) relative orientation to it.
Values are guestimated through a rather complex method, based on the empirical observation (i.e. from playing thousands of computer games starting from materially imbalanced positions) that short-range leapers with N moves have a value (33 + 0.7*N)*N centi-Pawn, where captures contribute twice as much as non-captures. To extend that to other classes of pieces their number of moves is calculated in a number of randomly generated positions with 25% filled boards, where the density of a certain color decreases to 0 at the furthest rank. And the average of this plus one standard deviation is then taken to plug into the formula for leapers.
The a does not stand for 'after' but for 'and again', which is the same as 'before'. So afsW means W before fsW: first a W step in any of the 4 directions, and then another step at 45 degrees (fs) relative orientation to it.
Values are guestimated through a rather complex method, based on the empirical observation (i.e. from playing thousands of computer games starting from materially imbalanced positions) that short-range leapers with N moves have a value (33 + 0.7*N)*N centi-Pawn, where captures contribute twice as much as non-captures. To extend that to other classes of pieces their number of moves is calculated in a number of randomly generated positions with 25% filled boards, where the density of a certain color decreases to 0 at the furthest rank. And the average of this plus one standard deviation is then taken to plug into the formula for leapers.