How does stockfish level 2 work in lichess?

[Uri Blass]

I saw that it played a lot of random moves against some beginner(in one case it even missed a mate in 1 in what seems to me a random move and lost the game later) and I wonder what is the probability that it is going to play a random move.

I also wonder if it is based on the code of latest stockfish or maybe based on the code of stockfish16 and if there are differences.

[purechess]

Lichess levels using SF use a combo of settings.

- limited time for search
- search depth
- UCI_Elo

I don't know if they changed that the last years.

You can see their approach in their code.

They use Fairy-Stockfish 14 - at least on Safari browser

[Uri Blass]

I am interested in the probability for random moves and I do not know where to find the code that they use.


Here is one game when stockfish level 2 lost against a beginner.
Stockfish missed 41.Rh8 mate and played 41.Rh3 that I guess to be a random move.

I am interested in the probability it play a random move and how to find it.

Limited time for search or search depth are clearly not relevant because they are not the reason it missed mate in 1 and I guess they are not relevant for the playing strength of stockfish level 2 .


https://lichess.org/4QOYcEMP/black#80

[ImNotStockfish]

https://github.com/lichess-org/fishnet/ ... #L237-L283
Fairy-Stockfish
Max 100 ms thinking time
Skill level -5
Max depth 5

https://github.com/lichess-org/lila/blo ... .scala#L91
Opening book of 1000-1200 rated players

[tapio]

Pure probability (and not more thoughtful algorithm) of playing the n-th best move would make weak playing stupid. Exactly what I see in low skill settings, doesn't take the offered queen, doesn't mate in one... I guess it's just not SFs priority.