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> the player who committed more blunders lost 86% of the time In some sense this is almost tautological. While finding an exact definition for a chess blunder

> the player who committed more blunders lost 86% of the time In some sense this is almost tautological. While finding an exact definition for a chess blunder isn't straightforward, here is one example from the Lichess UI: https://github.com/lichess-org/lila/blob/b527746b179cdde64382b07e4f267bf8a27810c1/ui/analyse/src/practice/practiceCtrl.ts#L118 https://github.com/lichess-org/lila/blob/b527746b179cdde6438... Basically, if you make a move which decreases your winning probability more than 14% over the best move, that's a blunder. But winning probability is a nonlinear function of stockfish centipawns. A drop in 100 centipawns when you're up 15 points isn't a blunder. When the game was equal, it is. Point is, by the time you know it's a blunder you already know something about the outcome of that move, that it swung the winning probability by more than 14%. So the analysis is kind of just measuring some function of winning probability and saying that it is highly correlated with winning probability.

matsemann 3y ago
Also, getting better changes what a blunder is. When I began, hanging my queen was a blunder. Then allowing a discovered check was a blunder. Then allowing the threat of a future discovered check affect my move is a blunder etc.
smatija 3y ago
These evaluation-centric definitions of blunder are a bit awkward though. Traditionally blunders were defined in more player-centric way: player blundered, when he made a mistake obvious enough, that a player of his strength is very unlikely to make. So what is a blunder for a strong player may merely be a mistake for a weaker player. Problem with evaluation-centric definition is that not all moves that worsen position by 14% are equally obvious - if you hang a queen in one that is certainly a blunder, if you miss a non-trivial sacrificial combination on the other hand...
- salamo 3y ago
  Chess.com is also definitely using an evaluation-centric definition to label moves as blunders. The issue is that this definition is also some function of the change in winning probability. > So what is a blunder for a strong player may merely be a mistake for a weaker player. Statistically this intuition appears to be correct. Your winning probability is still more than 25% when down a queen against an 800 rated player, but under 10% if playing a 2200: https://web.chessdigits.com/articles/when-should-you-resign#h.9rzdbhraiwgd https://web.chessdigits.com/articles/when-should-you-resign#... So it would make sense for the definition to take into account the opponent's Elo rating.
  - smatija 3y ago
    I agree - all attempts at automatic classification of blunder have same problem. This is why analysing games without engine still matters and is going to matter for foreseable future. Don't forget also impact of time control - shorter games lead to more mutual mistakes. While in 90+30 first big blunder should decide the game, in blitz it's just the beginning. Amusing example is Chessbrah speedruning to 2000, while hanging queen in every game: https://www.twitch.tv/videos/593176969 https://www.twitch.tv/videos/593176969
GuB-42 3y ago
Maybe a better analogy would be card counting in Blackjack. To be profitable (if it can be), card counting works with extremely tight margins, like a fraction of a percent per hand. It only turns a profit averaged out over many hands. But if you make a basic strategy blunder, you can lose the statistical benefits of maybe hundreds of perfectly played hands. That's why it may be better to play a simple strategy perfectly, than a more advanced but error prone strategy. That's also the reason why casinos love wannabe card counters. Their strategy may work in theory, but because of mistakes, the end result is worse for the player than playing basic strategy. Note about basic strategy: it is the optimal way of playing blackjack assuming each card draw is independent (so, no card counting), it is simple, and widely available and accepted in casinos. The player is at a loss (of course), but reasonably so. If you can play basic strategy consistently, you are better off than the vast majority of players.
- rileymat2 3y ago
  I feel ignorant, I thought with card counting you were still pretty much playing the simple strategy but altering bet sizes as your expectations of winning increased?
  - chiyc 3y ago
    It can also involve deviations in strategy based on the count, particularly with borderline hands.
  - Cushman 3y ago
    Your understanding is correct, more or less[0], but there are two parts to strategy: an inexpert counter is likely to be distracted, and to make errors from perfect play. They’re also likely to lose the count, and make errors in bet sizing. The net of those is worse than a non-counter playing perfectly, whose edge is slightly negative but who still stands a decent chance of making money on a given day. But note that’s a reason for casinos not to overtly discourage counting; they’ll still happily ban a player who is apparently counting well rather than roll the dice on whether they’re counting “well enough”. [0] Sibling points out that counters will make specific deviations from “naive” perfect play depending on the count, but that’s to push earnings up a bit on an already positive edge. There’s also the element of camouflage, where a really strong counter might deviate in ways that don’t hurt their earnings but make their play look less “counter-y”.
Certhas 3y ago
It's not tautological, though. Your position can gradually deteriorate until it is not salvageable anymore. In that situation we say that the opponent outplayed you. The fact that the switches in probability occur suddenly is highly relevant. One reason for this could be, that you are able to avoid this type of mistake 90% of the time. So during 9 out of ten moves, nothing changes. Then it does. So in this model, avoiding blunders means honing your skills to be able to apply all aspects of your mistake knowledge all the time. In another game, that is less blunder driven, it might be better to focus on getting more things right most of the time, rather than getting fewer things right all of the time. At this level, chess is a tactics game. Not a strategy game.
- Retric 3y ago
  It’s an issue of how the games are evaluated. At most skill levels a human being slowly outplayed is trading blunders from a computer’s perspective. For a 1400 a game where an 800 crushed a 500 is most likely a comedy of errors. For a GM that 1400 crushing a 1100 will similarly be filled with missed opportunities. And for a top chess engine on significant depth, most games are practically a slapstick comedy because the best of the best represent such a small fraction of overall players.
  - anamexis 3y ago
    I don't think that's true. Speaking as someone sub-1000 rated who plays lots of other people in the same region, the computer evals don't typically show a series of blunders. 1 or 2 blunders per game is common, but blunder-less games are also not uncommon. Just lots and lots of suboptimal but not terrible moves.
    - chongli 3y ago
      They may be referring to sub-1000 online rated. An 800 FIDE rated player is going to wipe the floor with an 800 chess.com rated player.
      - anamexis 3y ago
sjducb 3y ago
The point is that you are in control of whether you blunder or not. It’s more important to avoid obvious mistakes than to have a good strategy.
mtsyh 3y ago
Chess.com is more sophisticated than this in the treatment of blunders. They are divided into “misses” and “blunders”. In my experience, it appears that the difference between the two is that a “miss” is something the computer evaluates as unreasonable or difficult for a human to find. If you had found it, it would have been deemed a “brilliant” move, which is another analysis move type that chess.com has doesn’t have. Either that or a miss is failing to capitalize on an opponent’s blunder. It makes sense to chess players, since we consider missing an opportunity to capitalize on an opponent’s mistake to be distinct from unilaterally making one’s own position worse, even though to lichess those are going to both look like drops in the evaluation score.
- smatija 3y ago
  Chess.com isn't really more sophisticated than lichess - it's only trying to appear so. It's definition of blunder etc is still based only on engine evaluation. For example it marks as briliant all sound sacrifices, even the most routine ones. This is good marketing, but I doubt it's good analysis.
  - tainted_blood 3y ago
    It's just marketing to make players feel better about themselves. For example when i tried chess.com out they marked a simple queen sacrifice to deliver back rank-checkmate as brilliant even though it's an obvious move for any intermediate player with half a year of experience. Lichess does nothing of that marketing bs.
philipov 3y ago
It might be tautological, but it also happens to be correct! The Pareto rule applies: A beginner progressing to intermediate might quickly iron out the biggest blunders and by the time they're advanced get 80% there, but mastering that last 20% requires decades of practice.
incorrecthorse 3y ago
> In some sense this is almost tautological. Yes. The interesting property would be the reverse proposition: what percentage of victories are granted by not blundering? In amateur level chess, that number is very high. That's the point the author was trying to make.
deleted 3y ago
[deleted]
6gvONxR4sf7o 3y ago
The "don't blunder" advice applies to sports as well, where you hear it phrased in non-tautological ways frequently, typically something like "you need strong foundations." Even at the peak of college level, I remember winning and losing games because someone did something that you mostly stopped doing soon after learning the sport, like pass to a teammate who wasn't looking, or fumble the ball in a preventable way, or things like that. Some teams focused on fancy plays and corner cases while their fundamentals still failed frequently, leading to more losses due to bad fundamentals than than wins due to good advanced plays. That's how I read the "blunders" stuff. There's some small set of a priori known foundations you need which are fairly simple to keep from going wrong, which nonetheless lead to a large portion of failures/points given up/whatever.

matsemann 3y ago

Also, getting better changes what a blunder is. When I began, hanging my queen was a blunder. Then allowing a discovered check was a blunder. Then allowing the threat of a future discovered check affect my move is a blunder etc.

smatija 3y ago

These evaluation-centric definitions of blunder are a bit awkward though. Traditionally blunders were defined in more player-centric way: player blundered, when he made a mistake obvious enough, that a player of his strength is very unlikely to make. So what is a blunder for a strong player may merely be a mistake for a weaker player. Problem with evaluation-centric definition is that not all moves that worsen position by 14% are equally obvious - if you hang a queen in one that is certainly a blunder, if you miss a non-trivial sacrificial combination on the other hand...

salamo 3y ago
Chess.com is also definitely using an evaluation-centric definition to label moves as blunders. The issue is that this definition is also some function of the change in winning probability. > So what is a blunder for a strong player may merely be a mistake for a weaker player. Statistically this intuition appears to be correct. Your winning probability is still more than 25% when down a queen against an 800 rated player, but under 10% if playing a 2200: https://web.chessdigits.com/articles/when-should-you-resign#h.9rzdbhraiwgd https://web.chessdigits.com/articles/when-should-you-resign#... So it would make sense for the definition to take into account the opponent's Elo rating.
- smatija 3y ago
  I agree - all attempts at automatic classification of blunder have same problem. This is why analysing games without engine still matters and is going to matter for foreseable future. Don't forget also impact of time control - shorter games lead to more mutual mistakes. While in 90+30 first big blunder should decide the game, in blitz it's just the beginning. Amusing example is Chessbrah speedruning to 2000, while hanging queen in every game: https://www.twitch.tv/videos/593176969 https://www.twitch.tv/videos/593176969

GuB-42 3y ago

Maybe a better analogy would be card counting in Blackjack. To be profitable (if it can be), card counting works with extremely tight margins, like a fraction of a percent per hand. It only turns a profit averaged out over many hands. But if you make a basic strategy blunder, you can lose the statistical benefits of maybe hundreds of perfectly played hands. That's why it may be better to play a simple strategy perfectly, than a more advanced but error prone strategy. That's also the reason why casinos love wannabe card counters. Their strategy may work in theory, but because of mistakes, the end result is worse for the player than playing basic strategy. Note about basic strategy: it is the optimal way of playing blackjack assuming each card draw is independent (so, no card counting), it is simple, and widely available and accepted in casinos. The player is at a loss (of course), but reasonably so. If you can play basic strategy consistently, you are better off than the vast majority of players.

rileymat2 3y ago
I feel ignorant, I thought with card counting you were still pretty much playing the simple strategy but altering bet sizes as your expectations of winning increased?
- chiyc 3y ago
  It can also involve deviations in strategy based on the count, particularly with borderline hands.
- Cushman 3y ago
  Your understanding is correct, more or less[0], but there are two parts to strategy: an inexpert counter is likely to be distracted, and to make errors from perfect play. They’re also likely to lose the count, and make errors in bet sizing. The net of those is worse than a non-counter playing perfectly, whose edge is slightly negative but who still stands a decent chance of making money on a given day. But note that’s a reason for casinos not to overtly discourage counting; they’ll still happily ban a player who is apparently counting well rather than roll the dice on whether they’re counting “well enough”. [0] Sibling points out that counters will make specific deviations from “naive” perfect play depending on the count, but that’s to push earnings up a bit on an already positive edge. There’s also the element of camouflage, where a really strong counter might deviate in ways that don’t hurt their earnings but make their play look less “counter-y”.

Certhas 3y ago

It's not tautological, though. Your position can gradually deteriorate until it is not salvageable anymore. In that situation we say that the opponent outplayed you. The fact that the switches in probability occur suddenly is highly relevant. One reason for this could be, that you are able to avoid this type of mistake 90% of the time. So during 9 out of ten moves, nothing changes. Then it does. So in this model, avoiding blunders means honing your skills to be able to apply all aspects of your mistake knowledge all the time. In another game, that is less blunder driven, it might be better to focus on getting more things right most of the time, rather than getting fewer things right all of the time. At this level, chess is a tactics game. Not a strategy game.

Retric 3y ago
It’s an issue of how the games are evaluated. At most skill levels a human being slowly outplayed is trading blunders from a computer’s perspective. For a 1400 a game where an 800 crushed a 500 is most likely a comedy of errors. For a GM that 1400 crushing a 1100 will similarly be filled with missed opportunities. And for a top chess engine on significant depth, most games are practically a slapstick comedy because the best of the best represent such a small fraction of overall players.
- anamexis 3y ago
  I don't think that's true. Speaking as someone sub-1000 rated who plays lots of other people in the same region, the computer evals don't typically show a series of blunders. 1 or 2 blunders per game is common, but blunder-less games are also not uncommon. Just lots and lots of suboptimal but not terrible moves.
  - chongli 3y ago
    They may be referring to sub-1000 online rated. An 800 FIDE rated player is going to wipe the floor with an 800 chess.com rated player.
    - anamexis 3y ago

sjducb 3y ago

The point is that you are in control of whether you blunder or not. It’s more important to avoid obvious mistakes than to have a good strategy.

mtsyh 3y ago

Chess.com is more sophisticated than this in the treatment of blunders. They are divided into “misses” and “blunders”. In my experience, it appears that the difference between the two is that a “miss” is something the computer evaluates as unreasonable or difficult for a human to find. If you had found it, it would have been deemed a “brilliant” move, which is another analysis move type that chess.com has doesn’t have. Either that or a miss is failing to capitalize on an opponent’s blunder. It makes sense to chess players, since we consider missing an opportunity to capitalize on an opponent’s mistake to be distinct from unilaterally making one’s own position worse, even though to lichess those are going to both look like drops in the evaluation score.

smatija 3y ago
Chess.com isn't really more sophisticated than lichess - it's only trying to appear so. It's definition of blunder etc is still based only on engine evaluation. For example it marks as briliant all sound sacrifices, even the most routine ones. This is good marketing, but I doubt it's good analysis.
- tainted_blood 3y ago
  It's just marketing to make players feel better about themselves. For example when i tried chess.com out they marked a simple queen sacrifice to deliver back rank-checkmate as brilliant even though it's an obvious move for any intermediate player with half a year of experience. Lichess does nothing of that marketing bs.

philipov 3y ago

It might be tautological, but it also happens to be correct! The Pareto rule applies: A beginner progressing to intermediate might quickly iron out the biggest blunders and by the time they're advanced get 80% there, but mastering that last 20% requires decades of practice.

incorrecthorse 3y ago

> In some sense this is almost tautological. Yes. The interesting property would be the reverse proposition: what percentage of victories are granted by not blundering? In amateur level chess, that number is very high. That's the point the author was trying to make.

deleted 3y ago

[deleted]

6gvONxR4sf7o 3y ago

The "don't blunder" advice applies to sports as well, where you hear it phrased in non-tautological ways frequently, typically something like "you need strong foundations." Even at the peak of college level, I remember winning and losing games because someone did something that you mostly stopped doing soon after learning the sport, like pass to a teammate who wasn't looking, or fumble the ball in a preventable way, or things like that. Some teams focused on fancy plays and corner cases while their fundamentals still failed frequently, leading to more losses due to bad fundamentals than than wins due to good advanced plays. That's how I read the "blunders" stuff. There's some small set of a priori known foundations you need which are fairly simple to keep from going wrong, which nonetheless lead to a large portion of failures/points given up/whatever.