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Comment by Quarrelsome | Hacker News Reader

I believe its very much the arbitrary numbers we gave to pieces that we coded into our brute forced chess AIs that has allowed new chess AIs to be better.

As this article hinted, its understanding of piece value fluctuates based on the rules of the game but also as the game changes. Alpha Zero makes sacrifices human players wouldn't because they're too wedded to the idea that a queen is 9, a rook is 5 and a knight/bishop is 3.5. As flexible as a human mind gets is valuing a rook pair, bishop pair or knights if the position is closed.

This means that Alpha Go destroys the greedy Stockfish because Stockfish counts the numbers but Alpha Go counts the position of the entire board which is much more complicated.

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Stockfish evaluates the position of the entire board, e.g. mobility of pieces, how much opposing space they control, etc. But still, the evaluation function is hardcoded and weaker than AlphaZero.

Recently Stockfish introduced neural network evaluation.

https://blog.stockfishchess.org/post/625828091343896577/intr...

By that I just mean Alpha Go is assuming less about board state than StockFish and other conventional chess AIs do. Evidently the two engines have different assessments which is why Stockfish will greedily lap up a sacrifice by Alpha Zero onto to then lose because of it.

Stockfish parameters aren't arbitrary, hardcoded or static. Vast amount of computational power went into "tuning" those parameters to see which combination of values in which stage etc yields the best outcome. In that sense it's not dissimilar to Alpha Zero except the latter does this a lot more at much higher meta levels.

I think that stockfish does more than calculate piece values, it evaluates the strength of positions as a whole and is capable of performing some insane sacrifices itself.

No advanced chess engine is using a hard-coded value for pieces. It's not like all Stockfish does is tally up the pieces and summing their value.

I thought queen was 8, rook 5, and bishop/knights 3?

Generally, a queen is considered to be worth more than a rook and a bishop.

Also, knights and bishops are worth the same except they are not. Knights are good in closed play but you can't mate with two knights and a king. Bishops are definitely better when there is more space.

But, the value is just a simplification to help players assess situation. A piece which can't be played actively is worth nothing.

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