Answers.Body: <p><strong>Answering question 3 :</strong></p>
  <p><em>In existing GM+ games, how often would this even be applicable? Would any notable matches end differently?</em></p>
  <p>A very notable game is the last one of 2016 World Chess Championship <a href="https://en.wikipedia.org/wiki/World_Chess_Championship_2016#Game_16:_Carlsen%E2%80%93Karjakin_1%E2%80%930" rel="nofollow noreferrer">match</a> between Carlsen and Karjakin. Black resigned after 50.Qxh6!!</p>
  <p><a href="https://i.sstatic.net/wiJghjdY.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/wiJghjdY.png" alt="Final position" /></a></p>
  <p>Under the revenge move rule, Black could confidently play either 50...Kxh6 51.Rh8# or 50...gh6 51.Rxf7# and draw the game with the revenge move 51...Qg2#.</p>
  
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Answers.Text: Thanks! This is an awesome example, Karjakin came so close. Now I see why Carlsen ignored the last WCC, with all realistic challengers gone.
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Answers.Body: <p>This would just make white's life very difficult because white would have to engineer a situation where it's M1 for him and M2 (or more) for black. This kind of game is completely unfair because the opening move is unique in that it is unable to win the game by itself. So it would be completely unbalanced, and then the game would only be played between players of a very drastic gap in skill, with the skilled player taking white and the less skilled player taking black.</p>
  
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Answers.Text: Would it? While M1 vs M1 games happen, they're the little exciting moments of hardcore chess, rather than the norm.
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Answers.Text: @Therac : I am not sure. While they happen not so often on the board, I think they are quite common during calculation, and the evaluation of many variations would change.
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Answers.Text: @Therac, you make a valid point, but in chess...let's say you are white, and its M1 vs M1, then the rule that black has a revenge move kicks in - draw. Even though you went full Fischer and calculated a stunning checkmate combination...I think chess is not as general as we think it is. Every single moment in the game is a head-to-head deathmatch, and M1 vs M1 situations are the penultimate example. To answer the original question, everyone would be forced to play very defensively like Petrosian, and the number of draws would increase exponentially. I wouldn't play chess if that were the case.
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Body: <p>In a hypothetical minor variant, could White's first-move advantage be compensated for by Black's <em>right to last move</em>?</p>
  <p>Normally, White wins have White play N+1 plies to Black's N. How would the game change if White and Black always had an equal number of moves, i.e. Black could make their last move even if checkmated?</p>
  <p>To be specific, in this variant:</p>
  <ul>
  <li><a href="https://www.fide.com/FIDE/handbook/LawsOfChess.pdf" rel="nofollow noreferrer">Rule 5.1a</a> would be amended to &quot;The game is won by the player who has checkmated his opponent’s king, <em>unless their own king is checkmated at any time during the same game</em>. <em>If the black king is checkmated, black can still make one revenge move.</em>&quot;</li>
  <li>Rule 5.2f would be added, as &quot;<em>The game is drawn if both kings have been checkmated at any point in the game.</em>&quot;</li>
  <li>Rule 3.9 would be amended to &quot;No piece can be moved that will expose the king of the same colour to check. No piece can be moved that will leave that king in check, <em>except during the revenge move</em>.&quot;</li>
  </ul>
  <p>The reason it's a draw is that in 5.2f both players have reached a mating position in an equal number of moves. &quot;At any point&quot; is added in case black's revenge move gets them out of checkmate. That's still only a draw.</p>
  <p>There are <a href="https://chess.stackexchange.com/questions/27448/moving-into-check-for-a-draw-as-black-why-is-it-illegal-comparison-to-racing-k?rq=1">good reasons</a> these aren't the rules (who wants more draws?), but what I'm wondering is:</p>
  <ol>
  <li>Does it balance the game to equal, or does it make Black even stronger than White? In poker, last move is a big advantage.</li>
  <li>Would it only affect scoring, or also lead to different optimal play?</li>
  <li>In existing GM+ games, how often would this even be applicable? <strong>Would any notable matches end differently?</strong></li>
  </ol>
  <p>The third part could probably be answered with analyzing a few games.</p>
  <hr />
  <p>Own research:</p>
  <ul>
  <li><p>I've checked <a href="https://www.chessvariants.com/index/mainquery.php?type=Any&amp;category=Usual-Winning" rel="nofollow noreferrer">chessvariants</a> to look if this has already been tried, but it's too minor for a variant. There have been <a href="https://www.kcl.ac.uk/news/simple-rule-change-could-mean-check-mate-for-unfair-advantage-in-chess" rel="nofollow noreferrer">other balance attempts that work through move order</a>, but they affect the openings.</p>
  </li>
  <li><p>This rule breaks some puzzles, which use a mate-in-one threat to enforce forcing moves. Under new rules, removing the M1 threat before checkmating is more valuable than checkmating ASAP. All win puzzles still work the same if the player is black, and all draw puzzles if white. Some draw puzzles might get alternate solutions.</p>
  </li>
  <li><p>The wording of the check rule) has implications. Can the player expose a double-checked king to a <a href="https://chess.stackexchange.com/questions/34859/is-it-possible-to-be-in-check-by-three-pieces/34862#34862">triple check</a>, or even replace one check with another? Under this ultra-conservative wording, they can't. If designing this rule into a variant, I'd certainly prefer &quot;go wild&quot; for the revenge move.</p>
  </li>
  </ul>
  
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Comments.Text: **Comments have been [moved to chat](https://chat.stackexchange.com/rooms/156430/discussion-on-question-by-therac-how-much-would-chess-change-if-black-always-had); please do not continue the discussion here.** Before posting a comment below this one, please review the [purposes of comments](/help/privileges/comment). Comments that do not request clarification or suggest improvements usually belong as an [answer](/help/how-to-answer), on [meta], or in [chat]. Comments continuing discussion may be removed.
Comments.UserDisplayName: Brian Towers
Tags: <rules><checkmate><chess-variants><advantage>
Title: How much would chess change if Black always had the last move?
ThreadText: # How much would chess change if Black always had the last move?
  
  (Asked by: username_0 on 2023-07-23)
  
  In a hypothetical minor variant, could White's first-move advantage be compensated for by Black's *right to last move*?
  
  Normally, White wins have White play N+1 plies to Black's N. How would the game change if White and Black always had an equal number of moves, i.e. Black could make their last move even if checkmated?
  
  To be specific, in this variant:
  
  * [Rule 5.1a](https://www.fide.com/FIDE/handbook/LawsOfChess.pdf) would be amended to "The game is won by the player who has checkmated his opponent’s king, *unless their own king is checkmated at any time during the same game*. *If the black king is checkmated, black can still make one revenge move.*"
  * Rule 5.2f would be added, as "*The game is drawn if both kings have been checkmated at any point in the game.*"
  * Rule 3.9 would be amended to "No piece can be moved that will expose the king of the same colour to check. No piece can be moved that will leave that king in check, *except during the revenge move*."
  
  The reason it's a draw is that in 5.2f both players have reached a mating position in an equal number of moves. "At any point" is added in case black's revenge move gets them out of checkmate. That's still only a draw.
  
  There are [good reasons](https://chess.stackexchange.com/questions/27448/moving-into-check-for-a-draw-as-black-why-is-it-illegal-comparison-to-racing-k?rq=1) these aren't the rules (who wants more draws?), but what I'm wondering is:
  
  1. Does it balance the game to equal, or does it make Black even stronger than White? In poker, last move is a big advantage.
  2. Would it only affect scoring, or also lead to different optimal play?
  3. In existing GM+ games, how often would this even be applicable? **Would any notable matches end differently?**
  
  The third part could probably be answered with analyzing a few games.
  
  ---
  
  Own research:
  
  * I've checked [chessvariants](https://www.chessvariants.com/index/mainquery.php?type=Any&category=Usual-Winning) to look if this has already been tried, but it's too minor for a variant. There have been [other balance attempts that work through move order](https://www.kcl.ac.uk/news/simple-rule-change-could-mean-check-mate-for-unfair-advantage-in-chess), but they affect the openings.
  * This rule breaks some puzzles, which use a mate-in-one threat to enforce forcing moves. Under new rules, removing the M1 threat before checkmating is more valuable than checkmating ASAP. All win puzzles still work the same if the player is black, and all draw puzzles if white. Some draw puzzles might get alternate solutions.
  * The wording of the check rule) has implications. Can the player expose a double-checked king to a [triple check](https://chess.stackexchange.com/questions/34859/is-it-possible-to-be-in-check-by-three-pieces/34862#34862), or even replace one check with another? Under this ultra-conservative wording, they can't. If designing this rule into a variant, I'd certainly prefer "go wild" for the revenge move.
  
  **Tags:** rules, checkmate, chess-variants, advantage
  
  > **Comments:**
  > **username_1**: **Comments have been [moved to chat](https://chat.stackexchange.com/rooms/156430/discussion-on-question-by-username_0-how-much-would-chess-change-if-black-always-had); please do not continue the discussion here.** Before posting a comment below this one, please review the [purposes of comments](/help/privileges/comment). Comments that do not request clarification or suggest improvements usually belong as an [answer](/help/how-to-answer), on [meta], or in [chat]. Comments continuing discussion may be removed.  
  
  ---
  
  ## 2 answers
  
  ### Answer by username_2 on 2024-11-28. Score: 2
  
  **Answering question 3 :**
  
  *In existing GM+ games, how often would this even be applicable? Would any notable matches end differently?*
  
  A very notable game is the last one of 2016 World Chess Championship [match](https://en.wikipedia.org/wiki/World_Chess_Championship_2016#Game_16:_Carlsen%E2%80%93Karjakin_1%E2%80%930) between Carlsen and Karjakin. Black resigned after 50.Qxh6!!
  
  [![Final position](https://i.sstatic.net/wiJghjdY.png)](https://i.sstatic.net/wiJghjdY.png)
  
  Under the revenge move rule, Black could confidently play either 50...Kxh6 51.Rh8# or 50...gh6 51.Rxf7# and draw the game with the revenge move 51...Qg2#.
  
  > **Comments:**
  > **username_0**: Thanks! This is an awesome example, Karjakin came so close. Now I see why Carlsen ignored the last WCC, with all realistic challengers gone.  
  
  ---
  
  ### Answer by username_3 on 2024-11-28. Score: 1
  
  This would just make white's life very difficult because white would have to engineer a situation where it's M1 for him and M2 (or more) for black. This kind of game is completely unfair because the opening move is unique in that it is unable to win the game by itself. So it would be completely unbalanced, and then the game would only be played between players of a very drastic gap in skill, with the skilled player taking white and the less skilled player taking black.
  
  > **Comments:**
  > **username_0**: Would it? While M1 vs M1 games happen, they're the little exciting moments of hardcore chess, rather than the norm.  
  > **username_2**: @username_0 : I am not sure. While they happen not so often on the board, I think they are quite common during calculation, and the evaluation of many variations would change.  
  > **username_3**: @username_0, you make a valid point, but in chess...let's say you are white, and its M1 vs M1, then the rule that black has a revenge move kicks in - draw. Even though you went full Fischer and calculated a stunning checkmate combination...I think chess is not as general as we think it is. Every single moment in the game is a head-to-head deathmatch, and M1 vs M1 situations are the penultimate example. To answer the original question, everyone would be forced to play very defensively like Petrosian, and the number of draws would increase exponentially. I wouldn't play chess if that were the case.  
  
  ---
  
  