[Taek]

Yes modern AIs have an entire opening database and generally have cached the first 20+ moves of the game (for most common openings) from a database of very deep searches identifying the best move. This is absolutely a form of opening prep for AIs.

That said, even without that database a modern AI will completely topple the best human at every common chess variant. Humans cannot defeat modern AIs in chess like games.

[nilslindemann]

Like my answer below, that's wrong. Even I have achieved a few draws or even wins against Stockfish in training games, and I am FM strength. From time to time you are happy to reach a simple rook endgame which happens to be won and the engine doesn't anticipate that (horizon effect). You still draw or lose 90% of those but you win 10%.

[galkk]

Either the engine was misconfigured, the hardware you were playing on was glitching or you are omitting something. There is no chance in the world that you can beat stockfish in standard time control.

[baumy]

Would you be willing to bet money that you can beat a properly setup stockfish, no piece odds and even time controls? I'll give you literally any odds you name and let you try an unlimited number of times until you give up. 100% serious.

P.S: You should not take this bet. You will lose. You are mistaken if you think you beat stockfish.

[nilslindemann]

Further, if the engine does not use an opening database and the thinking time per game is the same, then the engine will usually make the same moves, so you can learn from your errors. There are just a few chess engines which "learn" per default and therefore change their moves, like BrainLearn.

[LogicalRisk]

That's an extraordinary claim. What level was Stockfish and what were the settings for these training games?