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Straggler
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Re: Finding game-changing moves
Reply #7 - 09/03/21 at 09:07:27
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an ordinary chessplayer wrote on 09/02/21 at 23:09:44:
As tp2205 noted, this is a common feature available in many types of software, e.g. Aquarium "Find Blunders", Arena "Automatic Analysis", Chess Assistant "Full Analysis", Fritz "Blunder Check", Hiarcs Chess Explorer "Analyse game", Shredder "Analyse Game"etc.

Thanks very much. As far as I can see, most of these only let you search for blunders within a single game, rather than a collection of games. But Chess Assistant does seem to allow the latter, and it costs considerably less than even the upgrade to CB16. I would really love to stop giving ChessBase my money.
  
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an ordinary chessplayer
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Re: Finding game-changing moves
Reply #6 - 09/02/21 at 23:09:44
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Straggler wrote on 09/02/21 at 09:35:35:
I think centipawn analysis is new to CB16, which I don't yet have. If I've understood correctly, the output shows the highest (and lowest) average scores over whole games, rather than the highest scores for individual moves.

I also do not have ChessBase 16 -- Centipawn Analysis seems to simply do the same automated analysis as Tactical Analysis, but with the added convenience of calculating a game average and saving all the averages to a text file. As a chess coach you could analyze a bunch of games for a new student and quickly get a useful overview. But for your own games the details are far more important than the average.

As tp2205 noted, this is a common feature available in many types of software, e.g. Aquarium "Find Blunders", Arena "Automatic Analysis", Chess Assistant "Full Analysis", Fritz "Blunder Check", Hiarcs Chess Explorer "Analyse game", Shredder "Analyse Game"etc.

tp2205 wrote on 09/02/21 at 10:42:45:
While I can understand the general worry about cheaters, I don't see how this tool could worsen the current situation.

Should make the situation better, for example I can run pgnspy on my own games to make sure I am not cheating. Smiley
  
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Re: Finding game-changing moves
Reply #5 - 09/02/21 at 10:42:45
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TopNotch wrote on 09/01/21 at 23:03:12:
@StragglerStraggler wrote on 09/01/21 at 18:44:46:
Does ChessBase provide an easy way to identify, from among all the games of a database, those moves which change the engine's evaluation by at least a specified amount? I can't find such a feature, but it would obviously be useful so it would be surprising if they haven't included it yet. I imagine a programmer could do it with some sort of script, but that would be way beyond my coding skills.


Wow! That is ambitious and more than a little naive imo. To be honest these kinds of discussions always make me a little nervous, because somehow I feel that with every new software tweek, no matter how well intentioned, usually ends up being exploited by engine cheaters to more easily disguise their deceit against unwitting opponents.

Sad but true.



Why Naive? That's what all the online tools at lichess.com, chess.com, etc do. Even scidb has support for this. Using something like python-chess anybody with a little experience with python (the tutorial should suffice) could write such a script (that is if the files are in a non-proprietary format like pgn).

While I can understand the general worry about cheaters, I don't see how this tool could worsen the current situation. All it does is look for mistakes in (partial) game or (much less likely) moves the engine could not evaluate properly initially.
  
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Straggler
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Re: Finding game-changing moves
Reply #4 - 09/02/21 at 09:35:35
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Thanks, everyone. Whether the idea is ambitious or naive would obviously depend on the size of (a) the database and (b) the difference in evaluation that you search for. I wasn't planning to trawl Megabase for minor errors! I have separate databases for my own games and my pupil's (and you'll be relieved to know that the apostrophe there is in the right place). I thought it might be illuminating to identify the (many) occasions on which I have converted a won position into a lost one in a single move, and see whether there are any common themes.

Thanks in particular to aoc for the manual reference. I think centipawn analysis is new to CB16, which I don't yet have. If I've understood correctly, the output shows the highest (and lowest) average scores over whole games, rather than the highest scores for individual moves. But I suppose the games with the most horrific blunders are also likely to be the ones with the highest average scores, so that might be the way to do it. Until now I hadn't seen any compelling reason to upgrade, but maybe this is it.
  
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TopNotch
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Re: Finding game-changing moves
Reply #3 - 09/01/21 at 23:03:12
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@StragglerStraggler wrote on 09/01/21 at 18:44:46:
Does ChessBase provide an easy way to identify, from among all the games of a database, those moves which change the engine's evaluation by at least a specified amount? I can't find such a feature, but it would obviously be useful so it would be surprising if they haven't included it yet. I imagine a programmer could do it with some sort of script, but that would be way beyond my coding skills.


Wow! That is ambitious and more than a little naive imo. To be honest these kinds of discussions always make me a little nervous, because somehow I feel that with every new software tweek, no matter how well intentioned, usually ends up being exploited by engine cheaters to more easily disguise their deceit against unwitting opponents.

Sad but true.

  

The man who tries to do something and fails is infinitely better than he who tries to do nothing and succeeds - Lloyd Jones Smiley
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dfan
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Re: Finding game-changing moves
Reply #2 - 09/01/21 at 21:12:40
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You say "game-changing moves", which is a neutral phrasing, but note that this would overwhelmingly return mistakes, since the only way that the engine's evaluation can go up after a move is if it missed how it good the move was beforehand because it didn't search deep enough.
  
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an ordinary chessplayer
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Re: Finding game-changing moves
Reply #1 - 09/01/21 at 20:40:23
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Straggler wrote on 09/01/21 at 18:44:46:
from among all the games of a database

I don't know if that would be so useful. You can do it for a selection of games using the Tactical Analysis or Centipawn Analysis features. https://download.chessbase.com/download/pdf/cb16-eng.pdf see 3.12.14 - 3.12.16 under the Engines section. The more games you choose, the less time you can devote to evaluating each move. If you wanted to do the whole database that way and store the information for later recall in the tree, the time per move would be comically short. Another issue is that engines and hardware improve all the time, so any stored evaluations would be less accurate than a new evaluation you could do today. As a practical matter you are better off selecting only a small number of "interesting" games and then doing a current analysis. For example, you could analyze your own latest games this way. Or if you had an upcoming match you could analyze your opponent's games.
  
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Straggler
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Finding game-changing moves
09/01/21 at 18:44:46
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Does ChessBase provide an easy way to identify, from among all the games of a database, those moves which change the engine's evaluation by at least a specified amount? I can't find such a feature, but it would obviously be useful so it would be surprising if they haven't included it yet. I imagine a programmer could do it with some sort of script, but that would be way beyond my coding skills.
  
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