> I knew that it was just a minmax with alpha beta pruning and a really good eval function. Now its not.

It is still "just" a minimax with alpha beta pruning, except the eval function is now a neural network. NNUE, to be more specific.

I highly advise anyone who is curious about chess engines, but hasn't heard about NNUE to read about it. I find this technology absolutely fascinating.

The key idea is that a neural network is structured in a way that makes it very cheap to calculate scores for similar positions. This means that during a tree search, each time you advance or backtrack you can update the score efficiently instead of recalculating it from scratch.

Good starting points to read more:

- https://en.wikipedia.org/wiki/Efficiently_updatable_neural_n...

- https://www.chessprogramming.org/NNUE