What is a blunder in chess?

Mon, 25 Sep 2023 20:47:30 -0800

What is a blunder in chess? The tension between the qualitative and quantitative answers to this question is at the heart of different approaches towards chess, and more broadly, how quantitative metrics may lack context, but qualitative metrics lack precision.

Qualitative answer

There are many qualitative answers to this question, especially when comparing “blunders” and “mistakes”:

“a move that negatively affects their position in a significant way” ~ chess.com
“severely worsens the player’s situation by allowing a loss of material, checkmate, or anything similar” ~ Wikipedia
“Blunders tend to be immediately refutable, while mistakes require planning to capitalize on.” ~ r/chess

An issue with these qualitative answers is that while their words may be correct, smart people may still disagree with their applicability at the margins. For a suboptimal move to have a “significant” negative effect, it requires that the opponent notices and takes advantage of it.

Evaluation on Luke Salamone's Blog

What is a blunder in chess?

Qualitative answer