Answers.Body: <p>Historically, the answer is &quot;no&quot;. Computers beat humans at blitz well before they beat humans at classical chess (<a href="https://en.wikipedia.org/wiki/Human%E2%80%93computer_chess_matches#Anand%E2%80%93REBEL_(1998)" rel="nofollow noreferrer">example</a>).</p>
  <p>Humans seldom play serious matches with a time handicap, so I'm not aware if there are statistics on how much elo a player gains by having 120 more minutes. With computers, the allocated time is less important than the depth it searches to - the difference between letting a computer think for 2 days vs. 1 day per move is much smaller than letting a computer think for 10 seconds vs. 5 seconds per move.</p>
  <p>If you look at depth, then the elo gain with increasing search depth is tremendous. It depends on the engine, but an order of magnitude estimate for going one move deeper is <a href="https://en.wikipedia.org/wiki/Belle_(chess_machine)#Performance_Analysis" rel="nofollow noreferrer">a couple hundred elo</a>.</p>
  
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Answers.Text: I think the historical answer is probably wrong for modern engines. The Deep Blue era engines were missing most of the pruning heuristics modern engines have. Both SF and LC0 have effective branching factors <2 compared to about 15-30 for simpler engines. This means that newer engines have significantly better scaling
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Answers.Text: @OscarSmith good point. Unfortunately we probably don't have better, more recent data =/
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Answers.Body: <p>This is kind of hard to answer because of how much better computers are than humans at all time controls, but according to <a href="https://chesspro-ru.translate.goog/guestnew/looknullmessage/?themeid=54&amp;id=15&amp;page=24&amp;_x_tr_sl=ru&amp;_x_tr_tl=en&amp;_x_tr_hl=en-US&amp;_x_tr_pto=wapp" rel="nofollow noreferrer">https://chesspro-ru.translate.goog/guestnew/looknullmessage/?themeid=54&amp;id=15&amp;page=24&amp;_x_tr_sl=ru&amp;_x_tr_tl=en&amp;_x_tr_hl=en-US&amp;_x_tr_pto=wapp</a>, there was a 100 game match between SF11 and Fruit, where SF had 8 seconds per game + .04 seconds per move compared to 140 minutes per game + 40 seconds per move for fruit. With these settings, SF was about 150 elo stronger than fruit, which is roughly super-GM strength. Since then, SF has gained approximately <a href="https://github.com/official-stockfish/Stockfish/discussions/3628#discussioncomment-1047728" rel="nofollow noreferrer">https://github.com/official-stockfish/Stockfish/discussions/3628#discussioncomment-1047728</a>, so SF at 1/4th second per game should be roughly the same strength as Magnus at a few hours per move.</p>
  
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Answers.Text: While interesting, the question is not 'how much time odds do computers need to give humans to be equally strong' but 'do computers have more or less of a disadvantage, assuming equal time on both sides, at fast vs slow controls' (taking as given that computers will dominate any time-control, but how big is the Elo gap?).
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Answers.Text: The problem is that at any fixed time control, it's pretty hard to even measure the elo difference between humans and computers.
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Answers.Text: I agree, which is why I haven't provided an answer. I'm only pointing out you haven't made an attempt to answer the actual question of this thread, which remains extremely interesting. However you slice the maths, there is a contradiction between two facts: (1) short time-controls are viewed as tactics-dominated and computers were much more superior at them much more early than at slow time-controls; (2) these days top engines appear to be multiple clear iterations of 100% win-rate stronger than top humans at slow controls*. How then did Andrew Tang win a 15s+0 game vs Leela?
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Answers.Text: *Legacy backtesting proves this - it's been show for example that Rybka 3 (which on a human scale should have been 3200-3300 by 2008) < Houdini 2 which lost a legacy match (if I remember right - can look for reference on Talkchess) against Stockfish 8 without a single draw in over 120 games. Stockfish 10 struggles to get draws now against Stockfish 14.
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Answers.Text: @MobeusZoom the match vs lc0 was from when lc0 was still months old and full of bugs (and the nets weren't fully trained).
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Answers.Text: I had an inkling the reason was something like that. (IIRC a slightly later prototype version of Leela scored only 0-2 draws in the bottom division of TCEC. This was just an early experiment in imitating AlphaZero then, not the serious competitor engine it is now. ) Then that forms an important part of an answer I should think
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Body: <p><strong>Question:</strong> Title question, basically: do engines have a larger advantage over a human at long or short time controls? Have any studies been done on this?</p>
  <hr />
  <p><strong>Context for the question:</strong> On a <a href="https://old.reddit.com/r/todayilearned/comments/sj23vu/til_no_human_has_beaten_a_computer_in_a_chess/" rel="nofollow noreferrer">reddit thread</a> yesterday someone pointed out that <a href="https://www.youtube.com/watch?v=FZVKvcKB_To" rel="nofollow noreferrer">Andrew Tang beat Leela</a> in an ultrabullet game around four years ago. I was astounded by this -- I would not have thought this possible. (Leela was rated around 3250 on Lichess at the time, so she had been trained quite a bit there) I mentioned this to a buddy of mine, and his contention was that humans will perform better against engines at shorter time control. I thought that was flat out wrong, but set out to prove that point.</p>
  <p>Unfortunately, I was not able to find much in the way of hard data. This best I could find was <a href="http://fastgm.de/ratio-tc-depth.pdf" rel="nofollow noreferrer">this experiment</a> done by the folks (guy?) who runs FGRL that compares search depth against time. It seems that doubling the amount of thinking time approximately increases the search-depth by 2-ply. I have no idea how search-depth corresponds to playing strength -- the best I could find was <a href="http://web.ist.utl.pt/diogo.ferreira/papers/ferreira13impact.pdf" rel="nofollow noreferrer">this paper</a> from 2013 that suggests that an increase in search depth of 2-ply is an increase in playing strength of approximately 120 rating points.</p>
  <p>So, my best guess at this point is that doubling the amount of thinking time increases the engines rating by around 120 rating points. When I made the argument that engines have a bigger advantage at shorter time controls, I did not expect a 2-ply increase in search depth to increase the playing strength by 120 rating points, I expected it to be considerably lower.</p>
  <p>Grandmasters also play exceptionally well at short time controls. How much do they gain by doubling the time. Is it 120 rating points? I don't know. Do you? This is what made me doubt my initial conclusion, and prompted this question.</p>
  <p>Is the 120 rating point increase in computer playing strength by doubling its thinking time a reasonable conclusion?</p>
  
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Comments.Text: Hey @Dargscisyhp ,  I don't exactly now why it was closed, but I think your question is either not really clear or may be perceived as trolling. It should be quite obvious, that engines have a far greater advantage at short time controls over humans.
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Comments.Text: I believe that the machine specs which the engine is running on is a factor.
Comments.UserDisplayName: hb20007
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Comments.Text: @Hauptideal It isn't obvious. Are you ignoring the counterexample the op gave in his first lines of Andrew Tang winning a 15s+0 game against Leela? Consensus is it's inconceivable for any human to win a classical game against Leela, even if they played thousands.
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Comments.Text: @Dargiscisyhp I would say the question can do with some limiting of scope to the key issue. You also sound like you would be happy with an estimate of how either human or computer strength individually vary with time-control, but on SE this should not be wrapped into one question with asking how large the differential is.
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Comments.Text: @MobeusZoom I'd be happy limiting the scope to exactly what the **question** section asks. Context was provided because when I posted just the text in the question section alone the question was closed. I provided some explanation in both the comment section and my post itself as to why I'm providing a context section, but the comments were subsequently deleted, and my post was edited to remove those explanations (though you can go through the edit history if you want to see them). Sorry for the confusion -- I've done the best I feel I can with what the moderation team has allowed.
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Comments.Text: Other than "accidents" like the game between Tang and Leela you post, I don't have much data to support my opinion, but the answer depends on what you mean by larger advantage. In a 100 games match, no mater the time control, the human has 0 chances to win the match. OTOH, in blitz the human can once in a while win a game, but they'll lost much more games than in a long time match. But in a long time match human has 0 chances to win a single game.
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Comments.Text: TLDR (thanks to oscarsmith for pointing it out) seems to be that Leela was an infant then and not a 'real engine'. At a 3250 rating on Lichess it should be substantially weaker than even Rybka (which might be 3250+ in FIDE classical on a human scale, and almost certainly better at blitz than slow controls), let alone any contemporary engine. It received opportunities for play solely on the basis of being an imitation effort of AlphaZero. We can guess Leela has absorbed thousands of rating points since the match with Andrew Tang.
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Comments.Text: Another piece of evidence to consider maybe: material odds matches (the only kind of competitive battle humans still have with engines). Kaufman has written a lot on what results Komodo should expect against humans of given rating at given time-controls. As a quick summary, it's much easier for Komodo to recover a substantial material deficit (like a Knight) at fast time-controls. (FWIW, currently Komodo is just short of par at rapid controls with an average 2500 GM after giving Knight odds.)
Comments.UserDisplayName: Mobeus Zoom
Tags: <engines>
Title: Do engines have a larger advantage over a human at long or short time controls?
ThreadText: # Do engines have a larger advantage over a human at long or short time controls?
  
  (Asked by: username_0 on 2022-02-03)
  
  **Question:** Title question, basically: do engines have a larger advantage over a human at long or short time controls? Have any studies been done on this?
  
  ---
  
  **Context for the question:** On a [reddit thread](https://old.reddit.com/r/todayilearned/comments/sj23vu/til_no_human_has_beaten_a_computer_in_a_chess/) yesterday someone pointed out that [Andrew Tang beat Leela](https://www.youtube.com/watch?v=FZVKvcKB_To) in an ultrabullet game around four years ago. I was astounded by this -- I would not have thought this possible. (Leela was rated around 3250 on Lichess at the time, so she had been trained quite a bit there) I mentioned this to a buddy of mine, and his contention was that humans will perform better against engines at shorter time control. I thought that was flat out wrong, but set out to prove that point.
  
  Unfortunately, I was not able to find much in the way of hard data. This best I could find was [this experiment](http://fastgm.de/ratio-tc-depth.pdf) done by the folks (guy?) who runs FGRL that compares search depth against time. It seems that doubling the amount of thinking time approximately increases the search-depth by 2-ply. I have no idea how search-depth corresponds to playing strength -- the best I could find was [this paper](http://web.ist.utl.pt/diogo.ferreira/papers/ferreira13impact.pdf) from 2013 that suggests that an increase in search depth of 2-ply is an increase in playing strength of approximately 120 rating points.
  
  So, my best guess at this point is that doubling the amount of thinking time increases the engines rating by around 120 rating points. When I made the argument that engines have a bigger advantage at shorter time controls, I did not expect a 2-ply increase in search depth to increase the playing strength by 120 rating points, I expected it to be considerably lower.
  
  Grandmasters also play exceptionally well at short time controls. How much do they gain by doubling the time. Is it 120 rating points? I don't know. Do you? This is what made me doubt my initial conclusion, and prompted this question.
  
  Is the 120 rating point increase in computer playing strength by doubling its thinking time a reasonable conclusion?
  
  **Tags:** engines
  
  > **Comments:**
  > **username_1**: Hey @username_0 ,  I don't exactly now why it was closed, but I think your question is either not really clear or may be perceived as trolling. It should be quite obvious, that engines have a far greater advantage at short time controls over humans.  
  > **username_2**: I believe that the machine specs which the engine is running on is a factor.  
  > **username_3**: @username_1 It isn't obvious. Are you ignoring the counterexample the op gave in his first lines of Andrew Tang winning a 15s+0 game against Leela? Consensus is it's inconceivable for any human to win a classical game against Leela, even if they played thousands.  
  > **username_3**: @Dargiscisyhp I would say the question can do with some limiting of scope to the key issue. You also sound like you would be happy with an estimate of how either human or computer strength individually vary with time-control, but on SE this should not be wrapped into one question with asking how large the differential is.  
  > **username_0**: @MobeusZoom I'd be happy limiting the scope to exactly what the **question** section asks. Context was provided because when I posted just the text in the question section alone the question was closed. I provided some explanation in both the comment section and my post itself as to why I'm providing a context section, but the comments were subsequently deleted, and my post was edited to remove those explanations (though you can go through the edit history if you want to see them). Sorry for the confusion -- I've done the best I feel I can with what the moderation team has allowed.  
  > **username_4**: Other than "accidents" like the game between Tang and Leela you post, I don't have much data to support my opinion, but the answer depends on what you mean by larger advantage. In a 100 games match, no mater the time control, the human has 0 chances to win the match. OTOH, in blitz the human can once in a while win a game, but they'll lost much more games than in a long time match. But in a long time match human has 0 chances to win a single game.  
  > **username_3**: TLDR (thanks to oscarsmith for pointing it out) seems to be that Leela was an infant then and not a 'real engine'. At a 3250 rating on Lichess it should be substantially weaker than even Rybka (which might be 3250+ in FIDE classical on a human scale, and almost certainly better at blitz than slow controls), let alone any contemporary engine. It received opportunities for play solely on the basis of being an imitation effort of AlphaZero. We can guess Leela has absorbed thousands of rating points since the match with Andrew Tang.  
  > **username_3**: Another piece of evidence to consider maybe: material odds matches (the only kind of competitive battle humans still have with engines). Kaufman has written a lot on what results Komodo should expect against humans of given rating at given time-controls. As a quick summary, it's much easier for Komodo to recover a substantial material deficit (like a Knight) at fast time-controls. (FWIW, currently Komodo is just short of par at rapid controls with an average 2500 GM after giving Knight odds.)  
  
  ---
  
  ## 2 answers
  
  ### Answer by username_5 on 2022-02-07. Score: 2
  
  Historically, the answer is "no". Computers beat humans at blitz well before they beat humans at classical chess ([example](https://en.wikipedia.org/wiki/Human%E2%80%93computer_chess_matches#Anand%E2%80%93REBEL_(1998))).
  
  Humans seldom play serious matches with a time handicap, so I'm not aware if there are statistics on how much elo a player gains by having 120 more minutes. With computers, the allocated time is less important than the depth it searches to - the difference between letting a computer think for 2 days vs. 1 day per move is much smaller than letting a computer think for 10 seconds vs. 5 seconds per move.
  
  If you look at depth, then the elo gain with increasing search depth is tremendous. It depends on the engine, but an order of magnitude estimate for going one move deeper is [a couple hundred elo](https://en.wikipedia.org/wiki/Belle_(chess_machine)#Performance_Analysis).
  
  > **Comments:**
  > **username_6**: I think the historical answer is probably wrong for modern engines. The Deep Blue era engines were missing most of the pruning heuristics modern engines have. Both SF and LC0 have effective branching factors <2 compared to about 15-30 for simpler engines. This means that newer engines have significantly better scaling  
  > **username_5**: @OscarSmith good point. Unfortunately we probably don't have better, more recent data =/  
  
  ---
  
  ### Answer by username_6 on 2022-02-06. Score: 1
  
  This is kind of hard to answer because of how much better computers are than humans at all time controls, but according to <https://chesspro-ru.translate.goog/guestnew/looknullmessage/?themeid=54&id=15&page=24&_x_tr_sl=ru&_x_tr_tl=en&_x_tr_hl=en-US&_x_tr_pto=wapp>, there was a 100 game match between SF11 and Fruit, where SF had 8 seconds per game + .04 seconds per move compared to 140 minutes per game + 40 seconds per move for fruit. With these settings, SF was about 150 elo stronger than fruit, which is roughly super-GM strength. Since then, SF has gained approximately <https://github.com/official-stockfish/Stockfish/discussions/3628#discussioncomment-1047728>, so SF at 1/4th second per game should be roughly the same strength as Magnus at a few hours per move.
  
  > **Comments:**
  > **username_3**: While interesting, the question is not 'how much time odds do computers need to give humans to be equally strong' but 'do computers have more or less of a disadvantage, assuming equal time on both sides, at fast vs slow controls' (taking as given that computers will dominate any time-control, but how big is the Elo gap?).  
  > **username_6**: The problem is that at any fixed time control, it's pretty hard to even measure the elo difference between humans and computers.  
  > **username_3**: I agree, which is why I haven't provided an answer. I'm only pointing out you haven't made an attempt to answer the actual question of this thread, which remains extremely interesting. However you slice the maths, there is a contradiction between two facts: (1) short time-controls are viewed as tactics-dominated and computers were much more superior at them much more early than at slow time-controls; (2) these days top engines appear to be multiple clear iterations of 100% win-rate stronger than top humans at slow controls*. How then did Andrew Tang win a 15s+0 game vs Leela?  
  > **username_3**: *Legacy backtesting proves this - it's been show for example that Rybka 3 (which on a human scale should have been 3200-3300 by 2008) < Houdini 2 which lost a legacy match (if I remember right - can look for reference on Talkchess) against Stockfish 8 without a single draw in over 120 games. Stockfish 10 struggles to get draws now against Stockfish 14.  
  > **username_6**: @MobeusZoom the match vs lc0 was from when lc0 was still months old and full of bugs (and the nets weren't fully trained).  
  > **username_3**: I had an inkling the reason was something like that. (IIRC a slightly later prototype version of Leela scored only 0-2 draws in the bottom division of TCEC. This was just an early experiment in imitating AlphaZero then, not the serious competitor engine it is now. ) Then that forms an important part of an answer I should think  
  
  ---
  
  