"how lichess works" - checkmate with bishop and knight

I totally believe you that it won't find the win.

And maybe I misunderstood your initial question. You question was referring to the lichess computer opponent level 8. And yes I think it would be possible to make it win by using endgame tablebases.

But that would also mean, it would play perfectly in tablebase range. And that is nothing a human would normally do in up to 7-Piece endgames. And the computer opponents are meant to be fun. And it's not fun to play someone making only best moves.

Been a while since I've looked at the source, but I'm pretty sure level 8 is capped at a 12 ply search.

That's still strong enough to play a pretty mean game of chess against humans at fast time controls, but with a cap at 12 ply it can definitely mess up KBNk.

SF has some special evaluation features that help guide it toward the solution of specific endgames, KBNk included, but it still needs to get deeper than 12 ply to win KBNk every time.

If you play against Stockfish on your machine with SF capped at a 12 ply search, it will frequently fail to convert, especially against best tablebase defense.

As to the 2500 rating, that's just a more or less arbitrary hard-coded value for it to display. It's not actually part of how its strength is capped (that's done with a combination of the Skill Level UCI option, max depth, and max search time).

hi to all, i want to take stock of the situation (sorry my english):
1) all of us know that Stockfish usually win endgame KBN (3400elo) ( ve see a game played on another PC; it's not important the opponent)
2) i don't know what were tablebases in chess
3) StockFish on lichess site could't win the endgame
4) i'm not a good player and i didn't a good the game (at 7th i should have lost in #13)
5) everything is wrote in game and i didn't any change on software on pc etc
now Only question is:
a)it is important for lichess.org having a software at the maximum level which could not win an endgame KBN?
b) someone of us thinks lichess.org should know this thing?
c) .... how we can close this post ?
:-)