I was really doing good in this blitz game but i was surprised that move 6 (white to move) was a blunder.
(I played e3 missing that I can attack the bishop and discover attack the queen and having good duo pawns that control the center by playing e4)
6. e4 is a double attack, hitting both queen and bishop, winning the bishop on f5.
Edited to add: As I understand it, the distinction between a mistake and a blunder is strictly the computer evaluation, i.e. how much the engine's evaluation changes with one's actual move vs. the best available move. In the case, it's a big swing, from +6.4 to +1.5. For comparison, a rook is worth about 5.
obviously a blunder because you miss to capture a whole bishop thereby creating a discovered attack on the queen. It is like throwing away a winning chance.
Here it’s pure maths (best engine move - your move)
delta 0,5-1 inacc.
d 1-2 mistake
d >2 blunder
In a mathematical sense:
inaccuracy does not exist
mistake (?): turns a won position into a drawn one or turns a drawn position into a lost one
blunder (??): turns a won position into a lost one
Best engine move depends on the engine.
If the engine would know, then no engine would be able to defeat another engine.