Is there any definition of "mistake" or "blunder"

I am a terrible player (1200s blitz) and when I look at my games they always come with a number of moves that are MISTAKES and BLUNDERS. Today I played a game where the engine tells me that I had 0 blunders and 0 mistakes. I went back and looked at it and there were some just terrible moves ... including one where the engine tells me I went from +27.8 all the way down to +11.8, and a few moves later when I went from +14.6 down to +6.3. Those feel pretty BLUNDERific to me. The first one doesn't get flagged as even an inaccuracy (let alone a mistake or a blunder), while the second one is shown as an inaccuracy.

Anyway, are there any rules for how bad a move has to be, to count as a blunder/mistake/inaccuracy?

Thanks for any help.

I would assume there are three 'set-points' in the code ... based on a single-ply cpl step-change ...

If you only lost a little cpl, then it's an inaccuracy, if it's say, around 100, then that's probably a mistake. I'd have to guess anything over 150 would be a blunder ...

For actual set-points you can refer to the Lichess codebase ...

Yes you're playing a human , don't pay too much attention to a machine.did you win the game , I'm wondering? xxx

@drwerewolf said in #1:
> I am a terrible player (1200s blitz) and when I look at my games they always come with a number of moves that are MISTAKES and BLUNDERS. Today I played a game where the engine tells me that I had 0 blunders and 0 mistakes. I went back and looked at it and there were some just terrible moves ... including one where the engine tells me I went from +27.8 all the way down to +11.8, and a few moves later when I went from +14.6 down to +6.3. Those feel pretty BLUNDERific to me. The first one doesn't get flagged as even an inaccuracy (let alone a mistake or a blunder), while the second one is shown as an inaccuracy.
>
> Anyway, are there any rules for how bad a move has to be, to count as a blunder/mistake/inaccuracy?
>
> Thanks for any help.

If your position is completely winning, it's hard to blunder. The 14.6 to 6.3 surprises me a bit though; I'd have imagined that registers as something, although 6.3 is very winning.

Tbh all values after 10 is basically destructive winning - it’s easy to win, blunders there mean you blundered a piece and made mate in 27 to +99.9, or you accidentally drew(threefold, stalemate), or you blundered mate in one.

EDIT: actually, blundering a piece but still winning +10.0 is usually counted as a mistake or inaccuracy

Besides the above mentioned 'set-points', sounds like there are also some other hueristics baked in too ... whatever, it's a machine and it's doing what it was programmed to do ... honestly, don't worry about it too much ...

Unfortunately, the traditional definitions of such terminology don't always coincide with engine definitions.

There's probably some room to improve this further, but all games would need to be re-analyzed.