Answers.Body: <p>Set aside the particular example you use, and instead assume that we have found some state where two moves are strictly equal under optimal play. Why would you favor one over the other? Let's focus on endgames, since that's the simplest.</p>
  <p>The answer, as pointed out by various comments, hinges on the fact that unless you're a masochist playing against a AlphaGo on max settings, you are unlikely to be engaged in optimal play, and thus the candidate moves are not equal in a practical sense. One position might be difficult, in the sense that there is only one drawing ply for you on each move that you have to successfully identify each time, while another is quite easy in that you have many options open to you on a given move. They are both equal under optimal play, but the latter is easier to manage.</p>
  <p>Go play around with the <a href="https://syzygy-tables.info" rel="nofollow noreferrer">Syzygy endgame tables</a> and compare various drawn positions, and in particular the mistakes that are available to the player to move. It's likely that you'll have the sense that some are easy draws, and some are obtuse. For instance, <a href="https://syzygy-tables.info/?fen=4k3/8/8/8/8/8/8/3K4_b_-_-_0_1" rel="nofollow noreferrer">KvK</a> is a clear draw (no possible mistakes), while <a href="https://syzygy-tables.info/?fen=4k3/6q1/3p4/8/8/8/2Q5/3K4_b_-_-_0_1" rel="nofollow noreferrer">KQvKQP</a> gives you many opportunities to make a mistake. <a href="https://syzygy-tables.info/?fen=4k3/p5q1/8/7n/8/N7/2Q5/3K4_b_-_-_0_1" rel="nofollow noreferrer">KQNvKQNP</a> is a tablebase draw in the arrangement, but note that if White plays the Nb5, then it converts to a winning endgame for Black. Seeing this is not at all obvious (at least to me), and other such mistakes are probably lurking. Similarly with different winning and losing endgames.</p>
  <p>The strategy here is subtle, and depends in part on your own endgame knowledge <em>and</em> your assessment of your opponent's. Suppose you are playing White and are given the chance to trade into this <a href="https://syzygy-tables.info/?fen=4k1q1/8/3p3b/1N6/8/8/2Q5/3K4_w_-_-_0_1" rel="nofollow noreferrer">KQNvKQBP endgame</a> or some other endgame that is also theoretically lost. You know with perfect play it's a loss for White, but there are some opportunities for Black to mess up and for White to steal the win. Do you take the trade? If you're playing against a computer, no, since it has access to the endgame tables. Similarly if you know that your opponent has lots of experience with such positions. If instead you suspect <em>you</em> have more experience, then you might be willing to take the risk to capitalize on your comparative advantage.</p>
  <p><strong>Analogy with the opening</strong></p>
  <p>I thought that switching focus to the opening might help clarify the thinking here.</p>
  <p>The two most common openings in chess are d2d4 and e2e4. I loaded up Stockfish 13 and had it evaluate each ply for a minute. The result is 23 CP for d2d4 and 22 CP for e2e4. Perhaps the former is objectively better, but for all practical purposes they are the same. Suppose you're in the final match of a tournament. Which one do you choose? Obviously, <em>the one you know more about.</em> If somehow you have managed to get to this point without ever playing d2d4, then you probably shouldn't start now, even though it is objectively 'better'.</p>
  <p>Similarly, you might avoid going into an opening that your opponent knows more about. Think about how Beth wrestled with whether to play the Sicilian against Borgov in <em>The Queen's Gambit</em>. Maybe if you're a genius, you can get away with playing to your opponent's strengths, but I think most of us would avoid challenging people on their own terf.</p>
  
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2021-03-10T23:22:52.113Z
Answers.LastActivityDate: 2021-03-11T02:21:35.603Z
Answers.LastEditDate: 2021-03-11T02:21:35.603Z
Answers.UserDisplayName: Nathan
Answers.Body: <p>Well, according to [Syzygy endgame tablebases](<a href="https://syzygy-tables.info/?fen=8/3k2PB/q7/8/4K3/8/8/8_w_-_-_0_1_" rel="nofollow noreferrer">https://syzygy-tables.info/?fen=8/3k2PB/q7/8/4K3/8/8/8_w_-_-_0_1_</a>, g8=R is a loss in 63 plies and g8=Q is a draw.  So g8=Q is definitely better.</p>
  
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Answers.Text: You got me! Perhaps I should add another light-coloured bishop to white so after g8=R, the game is still a draw.
Answers.UserDisplayName: Zuriel
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Answers.LastEditDate: 2021-03-10T19:33:56.607Z
Answers.UserDisplayName: DongKy
Answers.Body: <p>In this case, g8=Q is certainly better, since it makes black have to struggle for the draw, and g8=R would make white struggle for the draw.</p>
  
Answers.ContentLicense: CC BY-SA 4.0
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Answers.Text: Thank you! After g8=Q, black plays Qe6 and the game draws immediately.
Answers.UserDisplayName: Zuriel
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Answers.Text: Ah, cool, still you have to find that, while as black in the position with Q vs R+B it's not totally clear to me that it IS a draw and as indeed, as showed by another answer, it isn't.
Answers.UserDisplayName: pulsar512b
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Answers.UserDisplayName: pulsar512b
Answers.Body: <p>Yes, if it prolongs and &quot;shortens&quot; the game if you're losing or winning respectively.</p>
  <p>And there are tablebases for 7 pcs or less.</p>
  <p>Which means chess is solved with 7 pcs on the board.</p>
  
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Answers.LastActivityDate: 2020-08-04T01:43:12.450Z
Answers.UserDisplayName: Ikoz Manzukovski
Body: <p>Here is an example</p>
  <pre><code>[FEN &quot;8/3k2PB/q7/8/4K3/8/8/8 w - - 0 1&quot;]
  </code></pre>
  <p>One might intuitively say g8=Q is a much better move than g8=R. However, since they both lead to a draw, should we not conclude that g8=Q is as good as g8=R?</p>
  
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2020-08-03T07:53:15.917Z
Comments.Text: Not paying attention to fact mentioned in answer(R - loss; Q- draw) You have to evaluate possible chances not only perfect play if the moves are equal with perfect game one of them still may give you more practical chances - putting Queen definitely gives you more chances than Rook typically.
Comments.UserDisplayName: Drako
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2020-08-03T18:50:23.400Z
Comments.Text: That really depends on your definition of 'objective'. In game theory, where we model both players as rational self-interested decision-makers, there is indeed no reason why we would choose to play one move over another if they led to the same result. 'Objective' can also be used to mean what is considered good by two strong (but not perfect) players. E.g. the Sicilian Defence is objectively better than the Scandinavian Defence, even though they both probably lead to a draw with perfect play. Remember though that chess is a game which is much deeper than 'making the right moves'.
Comments.UserDisplayName: Joe
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2020-08-03T19:23:47.163Z
Comments.Text: Isn't it safe to say that promoting to either Rook or Bishop (under any situation, not just this one) is *at best* equal to promoting to Queen, but generally worse?  The only time you'd ever have a good reason to promote to anything other than Queen would be a Knight.
Comments.UserDisplayName: Darrel Hoffman
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2020-08-03T20:09:28.823Z
Comments.Text: @DarrelHoffman, There are situations where promoting to a Rook or Bishop is superior to promoting to a Queen, because promoting to a Queen would give a stalemate.
Comments.UserDisplayName: Akavall
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2020-08-03T20:49:45.190Z
Comments.Text: @DarrelHoffman  almost.  I saw a game where promoting to a rook won but the queen did not.   Might have been a problem not an OTB game.
Comments.UserDisplayName: edwina oliver
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2020-08-03T22:44:47.163Z
Comments.Text: I guess reading these answers, why bother about objectivity in chess! :D We would all care more about what would be easier to play, the most subjective thing there is. Next time when I get a queen I will remember how subjective I am. Cheers.
Comments.UserDisplayName: David Miedema
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2020-08-04T04:45:04.757Z
Comments.Text: Underpromotions to Rook and Bishop happened in actual games: https://www.chessgames.com/perl/chesscollection?cid=1004293
Comments.UserDisplayName: Akavall
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2021-03-11T12:27:14.287Z
Comments.Text: Since we are not chessbots, but humans, I say intuition is correct. *Any* game like chess, without chance and with complete information, and zero sum outcome, between two perfect players, would be completely pointless from the start.
Comments.UserDisplayName: Hauke Reddmann
Tags: <analysis><pawn-promotion>
Title: Is one move considered as objectively better than another if they both lead to the same result?
ThreadText: # Is one move considered as objectively better than another if they both lead to the same result?
  
  (Asked by: username_0 on 2020-08-03)
  
  Here is an example
  [FEN "8/3k2PB/q7/8/4K3/8/8/8 w - - 0 1"]
  
  One might intuitively say g8=Q is a much better move than g8=R. However, since they both lead to a draw, should we not conclude that g8=Q is as good as g8=R?
  
  **Tags:** analysis, pawn-promotion
  
  > **Comments:**
  > **username_1**: Not paying attention to fact mentioned in answer(R - loss; Q- draw) You have to evaluate possible chances not only perfect play if the moves are equal with perfect game one of them still may give you more practical chances - putting Queen definitely gives you more chances than Rook typically.  
  > **username_2**: That really depends on your definition of 'objective'. In game theory, where we model both players as rational self-interested decision-makers, there is indeed no reason why we would choose to play one move over another if they led to the same result. 'Objective' can also be used to mean what is considered good by two strong (but not perfect) players. E.g. the Sicilian Defence is objectively better than the Scandinavian Defence, even though they both probably lead to a draw with perfect play. Remember though that chess is a game which is much deeper than 'making the right moves'.  
  > **username_3**: Isn't it safe to say that promoting to either Rook or Bishop (under any situation, not just this one) is *at best* equal to promoting to Queen, but generally worse?  The only time you'd ever have a good reason to promote to anything other than Queen would be a Knight.  
  > **username_4**: @DarrelHoffman, There are situations where promoting to a Rook or Bishop is superior to promoting to a Queen, because promoting to a Queen would give a stalemate.  
  > **username_5**: @DarrelHoffman  almost.  I saw a game where promoting to a rook won but the queen did not.   Might have been a problem not an OTB game.  
  > **username_6**: I guess reading these answers, why bother about objectivity in chess! :D We would all care more about what would be easier to play, the most subjective thing there is. Next time when I get a queen I will remember how subjective I am. Cheers.  
  > **username_4**: Underpromotions to Rook and Bishop happened in actual games: https://www.chessgames.com/perl/chesscollection?cid=1004293  
  > **username_7**: Since we are not chessbots, but humans, I say intuition is correct. *Any* game like chess, without chance and with complete information, and zero sum outcome, between two perfect players, would be completely pointless from the start.  
  
  ---
  
  ## 4 answers
  
  ### Answer by username_8 on 2021-03-10. Score: 2 | Accepted answer
  
  Set aside the particular example you use, and instead assume that we have found some state where two moves are strictly equal under optimal play. Why would you favor one over the other? Let's focus on endgames, since that's the simplest.
  
  The answer, as pointed out by various comments, hinges on the fact that unless you're a masochist playing against a AlphaGo on max settings, you are unlikely to be engaged in optimal play, and thus the candidate moves are not equal in a practical sense. One position might be difficult, in the sense that there is only one drawing ply for you on each move that you have to successfully identify each time, while another is quite easy in that you have many options open to you on a given move. They are both equal under optimal play, but the latter is easier to manage.
  
  Go play around with the [Syzygy endgame tables](https://syzygy-tables.info) and compare various drawn positions, and in particular the mistakes that are available to the player to move. It's likely that you'll have the sense that some are easy draws, and some are obtuse. For instance, [KvK](https://syzygy-tables.info/?fen=4k3/8/8/8/8/8/8/3K4_b_-_-_0_1) is a clear draw (no possible mistakes), while [KQvKQP](https://syzygy-tables.info/?fen=4k3/6q1/3p4/8/8/8/2Q5/3K4_b_-_-_0_1) gives you many opportunities to make a mistake. [KQNvKQNP](https://syzygy-tables.info/?fen=4k3/p5q1/8/7n/8/N7/2Q5/3K4_b_-_-_0_1) is a tablebase draw in the arrangement, but note that if White plays the Nb5, then it converts to a winning endgame for Black. Seeing this is not at all obvious (at least to me), and other such mistakes are probably lurking. Similarly with different winning and losing endgames.
  
  The strategy here is subtle, and depends in part on your own endgame knowledge *and* your assessment of your opponent's. Suppose you are playing White and are given the chance to trade into this [KQNvKQBP endgame](https://syzygy-tables.info/?fen=4k1q1/8/3p3b/1N6/8/8/2Q5/3K4_w_-_-_0_1) or some other endgame that is also theoretically lost. You know with perfect play it's a loss for White, but there are some opportunities for Black to mess up and for White to steal the win. Do you take the trade? If you're playing against a computer, no, since it has access to the endgame tables. Similarly if you know that your opponent has lots of experience with such positions. If instead you suspect *you* have more experience, then you might be willing to take the risk to capitalize on your comparative advantage.
  
  **Analogy with the opening**
  
  I thought that switching focus to the opening might help clarify the thinking here.
  
  The two most common openings in chess are d2d4 and e2e4. I loaded up Stockfish 13 and had it evaluate each ply for a minute. The result is 23 CP for d2d4 and 22 CP for e2e4. Perhaps the former is objectively better, but for all practical purposes they are the same. Suppose you're in the final match of a tournament. Which one do you choose? Obviously, *the one you know more about.* If somehow you have managed to get to this point without ever playing d2d4, then you probably shouldn't start now, even though it is objectively 'better'.
  
  Similarly, you might avoid going into an opening that your opponent knows more about. Think about how Beth wrestled with whether to play the Sicilian against Borgov in *The Queen's Gambit*. Maybe if you're a genius, you can get away with playing to your opponent's strengths, but I think most of us would avoid challenging people on their own terf.
  
  
  ---
  
  ### Answer by username_9 on 2020-08-03. Score: 10
  
  Well, according to [Syzygy endgame tablebases](<https://syzygy-tables.info/?fen=8/3k2PB/q7/8/4K3/8/8/8_w_-_-_0_1_>, g8=R is a loss in 63 plies and g8=Q is a draw. So g8=Q is definitely better.
  
  > **Comments:**
  > **username_0**: You got me! Perhaps I should add another light-coloured bishop to white so after g8=R, the game is still a draw.  
  
  ---
  
  ### Answer by username_10 on 2020-08-03. Score: 5
  
  In this case, g8=Q is certainly better, since it makes black have to struggle for the draw, and g8=R would make white struggle for the draw.
  
  > **Comments:**
  > **username_0**: Thank you! After g8=Q, black plays Qe6 and the game draws immediately.  
  > **username_10**: Ah, cool, still you have to find that, while as black in the position with Q vs R+B it's not totally clear to me that it IS a draw and as indeed, as showed by another answer, it isn't.  
  
  ---
  
  ### Answer by username_11 on 2020-08-04. Score: 0
  
  Yes, if it prolongs and "shortens" the game if you're losing or winning respectively.
  
  And there are tablebases for 7 pcs or less.
  
  Which means chess is solved with 7 pcs on the board.
  
  
  ---
  
  