What I have read is that the latest generation of AI programs learn how to win at chess, or any other game, simply by knowing the rules and playing millions of games against itself. No general strategies are given to the computer. There has to be more to it.

I have done Web searches on this and have not found an answer. All I found were ways of minimizing the amount of look-ahead, assuming some way of evaluating each position. But how are positions evaluated?