I made a few minimax based AIs for games in uni, but I had always wondered how I would calculate score. How are these point systems made? Are they just educated guesses? How far can minimax take you as far as skill level?
I'm currently in the process of building my own chess AI (in python), and I'm using as a score a weighted combination of the material and of the number of squares controlled by each side. I am planing to experiment with weighting more the squares that are closed to the opponent's king, and possibly to improve the evaluation function using reinforcement learning.
That said, my program is currently pretty weak, first I have to optimize its calculation speed to it can calculate deeper.
A pure minimax engine isn't that hard to beat because the engine will be basically playing random moves during the opening phase. An opening repertoire + minimax on a modern computer will beat casual players (probably 1700-1900 Elo if I had to guess). You also have to do some good time management.