Wondering how these are defined
Obviously a blunder is worse than a mistake.
How the Lichess analysis tool defines them, I'm not quite sure. It may simply be according to how much centipawn loss (reduction in the evaluation score of the player's position) the move causes, but there may be more to it than that. I'd be interested to know.
In normal chess-speak, a blunder is a mistake which is both catastrophic and obvious. A mistake need not be either.
@Brian-E said in #2:
> Obviously a blunder is worse than a mistake.
>
> How the Lichess analysis tool defines them, I'm not quite sure. It may simply be according to how much centipawn loss (reduction in the evaluation score of the player's position) the move causes, but there may be more to it than that. I'd be interested to know.
>
> In normal chess-speak, a blunder is a mistake which is both catastrophic and obvious. A mistake need not be either.
If I remember correctly, I once saw someone complain about 20 c3 (in the game, https://www.chessgames.com/perl/chessgame?gid=1096564 , 1 d4 e6 2 e4 d5 3 Nc3 dxe4 4 Nxe4 Nd7 5 Nf3 Ngf6 6 Bd3 Be7 7 O-O Nxe4 8 Bxe4 Nf6 9 Bd3 b6 10 Ne5 O-O 11 Nc6 Qd6 12 Qf3 Bd7 13 Nxe7+ Qxe7 14 Bg5 Rac8 15 Rfe1 Rfe8 16 Qh3 Qd6 17 Bxf6 gxf6 18 Qh6 f5 19 Re3 Qxd4 20 c3 1-0) being identified as a blunder by a machine, indicating that 20 Rg3+ would have achieved an ~6.4 advantage instead of the ~3.3 advantage resulting from 20 c3.
a mistake makes your position worse. A blunder makes it losing
A blunder is when you hold your head in your hands and say out loud , why did I do that?!?, a mistake you might not notice xxx lol
@Brightonian29 said in #5:
> a mistake makes your position worse.
> A blunder makes it losing
At https://lichess.org/forum/general-chess-discussion/how-can-i-improve-positional-chess-i-keep-losing-because-i-get-myself-into-a-bad-position?page=4 , in the game, httpscolon//lichess.org/FQfZFcX8 , after 1 e4 e5 2 Nf3 Nc6 3 Bc4 f5 4 exf5 d5 5 Bb5 e4, the machine apparently characterized 6 Bxc6+ as a "blunder", while believing that 6 Ne5 would have given a "2.66" advantage to White, whereas 6 Bxc6+ gave a "0.27" advantage to Black.
You have to source code and read from there. Basically your computer evaluation is mapped to expected score (bit like probability to win) compared similarly to expected score after your move. If change is above some threshold it is classifies as mistake and as a bluder on a another limit.
In general outside lichess analysis people will not agree on definitio of bluder. I have heard two and they were quite different.
I agree that the definitio of bluder seems to vary somewhat from one person to another.
"Blunder A horrible mistake that hangs material or makes enormous positional or tactical concessions." - IM Jeremy Silman (1999)
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