Answers.Body: <p>If I understand your proposal, I think that the constraint that you are imposing would make it too easy to defeat the poor GM. Let's imagine the following pair of games with the GM playing Black:</p>
  
  <pre><code>1. e4 e5
  2. Qh5 Nf6
  3. Qxf7#
  
  1. e4 e5
  2. Qf3 Nf6
  3. a3
  </code></pre>
  
  <p>Qxf7 on the first game is "checkmate" because even though Black would simply capture the queen in a normal game, they can't do it here because they can't make the same move on the second board.</p>
  
Answers.ContentLicense: CC BY-SA 4.0
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Answers.Text: How did the queen go from h5 to f6?
Answers.UserDisplayName: D M
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Answers.Text: Sorry, silly typo!
Answers.UserDisplayName: itub
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Answers.Text: There's one thing you don't address.  What if the players can't see each other's boards, and *both* play this?
Answers.UserDisplayName: D M
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Answers.Text: You are right, Qxf7 would only make sense if the players are cooperating. If they are not, I think even by playing normally they would still have a great advantage because the GM would often be unable to make even the most obvious moves. Let's say one player decides to trade a bishop for a knight and is pleasantly surprised that the GM is unable to recapture!
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Answers.Body: <p>It would be extremely rare for a single move to be good in 2 separate and random situations, or even possible. That being the case if the players were at least 1200 strength the gm would be crushed.</p>
  
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Body: <p>Consider two simultaneous matches in which a GM plays against Players A and B, constrained by the rule that the GM must make identical board moves in both games. Players A and B can play as usual.</p>
  
  <p>Thus, for example, if Player A takes one of the GM's pawns, but Player B does not, then the GM forever loses the ability to move that pawn on Player B's board as well.</p>
  
  <p>The GM only wins by winning against both Players. We can also stipulate two versions, in one of which Players A and B can cooperate, and in the other of which they cannot.</p>
  
  <p>Question: Could two average Players A and B always win against the GM in this setup? Would it matter if they are allowed to cooperate or not?</p>
  
  <p>(I'm not necessarily looking for a mathematical demonstration of the answer, though if there is a simple winning strategy, that would be nice. I would be glad to hear from good players about what they think would happen.)</p>
  
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Comments.CreationDate: 2018-06-08T16:32:32.220Z
Comments.Text: " if Player A takes one of the GM's pawns, but Player B does not, then the GM forever loses the ability to move that pawn on Player B's board as well." So, not the game of chess we know. Or to put it another way, "If the moon were made of green cheese could X happen".
Comments.UserDisplayName: Brian Towers
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Comments.Text: @BrianTowers "So, not the game of chess we know." - That's why it's got the "chess-variants" tag?
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Comments.CreationDate: 2018-06-08T17:44:14.123Z
Comments.Text: @DM Adding the "chess-variants" tag does not make it a chess-variant. Nobody in the world plays this "variant" or ever has and for a reason. It is simply stupid! The question looks like it is just trolling by a new account created today. Is it a sock-puppet account?
Comments.UserDisplayName: Brian Towers
Tags: <chess-variants><simultaneous>
Title: Simul in which the GM has to make identical moves
ThreadText: # Simul in which the GM has to make identical moves
  
  (Asked by: username_0 on 2018-06-08)
  
  Consider two simultaneous matches in which a GM plays against Players A and B, constrained by the rule that the GM must make identical board moves in both games. Players A and B can play as usual.
  
  Thus, for example, if Player A takes one of the GM's pawns, but Player B does not, then the GM forever loses the ability to move that pawn on Player B's board as well.
  
  The GM only wins by winning against both Players. We can also stipulate two versions, in one of which Players A and B can cooperate, and in the other of which they cannot.
  
  Question: Could two average Players A and B always win against the GM in this setup? Would it matter if they are allowed to cooperate or not?
  
  (I'm not necessarily looking for a mathematical demonstration of the answer, though if there is a simple winning strategy, that would be nice. I would be glad to hear from good players about what they think would happen.)
  
  **Tags:** chess-variants, simultaneous
  
  > **Comments:**
  > **username_1**: " if Player A takes one of the GM's pawns, but Player B does not, then the GM forever loses the ability to move that pawn on Player B's board as well." So, not the game of chess we know. Or to put it another way, "If the moon were made of green cheese could X happen".  
  > **username_2**: @BrianTowers "So, not the game of chess we know." - That's why it's got the "chess-variants" tag?  
  > **username_1**: @DM Adding the "chess-variants" tag does not make it a chess-variant. Nobody in the world plays this "variant" or ever has and for a reason. It is simply stupid! The question looks like it is just trolling by a new account created today. Is it a sock-puppet account?  
  
  ---
  
  ## 2 answers
  
  ### Answer by username_3 on 2018-06-08. Score: 4
  
  If I understand your proposal, I think that the constraint that you are imposing would make it too easy to defeat the poor GM. Let's imagine the following pair of games with the GM playing Black:
  1. e4 e5
  2. Qh5 Nf6
  3. Qxf7#
  
  1. e4 e5
  2. Qf3 Nf6
  3. a3
  
  Qxf7 on the first game is "checkmate" because even though Black would simply capture the queen in a normal game, they can't do it here because they can't make the same move on the second board.
  
  > **Comments:**
  > **username_2**: How did the queen go from h5 to f6?  
  > **username_3**: Sorry, silly typo!  
  > **username_2**: There's one thing you don't address.  What if the players can't see each other's boards, and *both* play this?  
  > **username_3**: You are right, Qxf7 would only make sense if the players are cooperating. If they are not, I think even by playing normally they would still have a great advantage because the GM would often be unable to make even the most obvious moves. Let's say one player decides to trade a bishop for a knight and is pleasantly surprised that the GM is unable to recapture!  
  
  ---
  
  ### Answer by username_4 on 2018-06-10. Score: 3
  
  It would be extremely rare for a single move to be good in 2 separate and random situations, or even possible. That being the case if the players were at least 1200 strength the gm would be crushed.
  
  
  ---
  
  