(See also this related question and this related off-site discussion.)
Do state-of-the-art chess AIs still normally start games in human-compiled opening books of master games?
Years ago, as far as I know, state-of-the-art chess AIs started games in opening books. That is, years ago, to choose their first few moves, rather than calculating, chess AIs instead consulted databases of master games.
Do chess AIs still do that?
If you wish to know why I ask, more than 20 years ago, I owned a dedicated chess computer like one of these. The computer would instantly play each of its first several moves, apparently without thinking. The computer would slow down and start thinking only after
- it had exhausted the book or
- its human opponent had made a poor move, deviating from the book.
Nowadays, however, playing on Lichess, where the Stockfish AI is available for post mortem, I notice no obvious sign that Stockfish were consulting anything other than its own analyses.
(One suspects that various interesting things could be written on the topic. My knowledge of chess AIs is limited. I may or may not have posed the question optimally. Therefore, feel free to interpret the question broadly at your discretion.)