Answers.Body: <p>Interesting variant, a few random thoughts.</p>
  <p>Firstly need to clarify whether all the moves must be legal in the position facing the player, or alternatively that they play a sequence. (E.g. Is 1. a2-a4 &amp; Ra1-a3 legal?)</p>
  <ul>
  <li><p>If the former, then an exception is required that we don't worry about being in check until all the moves have been played.</p>
  </li>
  <li><p>If the latter then need to confirm whether it is ok in an intermediate position to be in check or to check the opponent.</p>
  </li>
  </ul>
  <p>Assuming the latter, checkmate is not impossible: each defender can only move once, but it’s certainly harder. Scholar’s mate is no longer checkmate, since Back can escape by d7–d5 Qd8-d6 Ke8-d8. But more effective is e7-e6 Ke8xf7 now the bishop guard on f7 is interrupted.</p>
  <p>Nevertheless, it appears that the game must be massively in White’s favour. I’m guessing that White has forced mate in 3.</p>
  <p>Suppose we pick k with 0&lt;k&lt;16 so that we say White can only move k units on their first turn. After that there is no limit for either players. For some k, the game should be “balanced”, although that term itself would require better definition.</p>
  <p>Have you tried playing this game?</p>
  
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Answers.Text: No, I'm going to try playing it soon with a friend.  Would be interesting if there was a forced mate in N moves.  I like the purity of each piece being able to move during its turn, but the game would of course not work if there is a forced mate in N moves from that.
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Answers.Text: Incidentally the unlimited rising k variant is solved for White; but k was > the number of pieces per side on the final position at the time. I've played kung fu chess; and I have a guess that limiting to one move per piece per turn shouldn't be a forced mate for White.
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Answers.Text: Re the rules: You can probably just steal the rules from [progressive chess](https://www.chessvariants.com/multimove.dir/progressive.html) or another "more than one move per turn" variant.
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Answers.Body: <p>According to <a href="https://www.chessvariants.com/books.dir/ecv.html" rel="nofollow noreferrer"><em>The Encyclopedia of Chess Variants</em></a> (<strong>ECV</strong>) by <a href="https://en.wikipedia.org/wiki/David_Pritchard_(chess_player)" rel="nofollow noreferrer">David B. Pritchard</a>, chess variants based on this idea have been invented at least four times. The following descriptions are copied from <strong>ECV</strong>. (The names Battle Chess and Omni Chess have also been used for other chess variants. Swarm Chess was mentioned in a comment by Noam D. Elkies.)</p>
  <p><strong>BATTLE CHESS</strong> aka <strong>RATUSHNY'S GAME</strong> Origins unknown; quoted in a letter by Russell Chauvenet (<em>Chess</em> Jan 1944). Each player can, but is not obliged to, move every pawn and piece once in a turn. Multiple checks are possible. Tense play, with White holding a considerable advantage.</p>
  <p><strong>HURRICANE CHESS</strong> (1970s?) Every man may move once per turn. At no time during the turn may a player put himself in check. A player in check must get out of check on the first move of a turn.</p>
  <p><strong>OMNI CHESS</strong> Richard Fireman and Bob Gorga (1979). Each player has the right to move any number of his men once each on a turn. Castling counts as both K. and R. moves. Multiple checks are possible. A player need only escape check at the end of a turn. One of the first games played between the inventors:<br />
  <em>White</em> <strong>Richard Fireman</strong> <em>Black</em> <strong>Bob Gorga</strong> <strong>1</strong> (W) e4 d4 Bc4 Ne2 0-0 Qd3 a3 b4 f4 Bb2 Nc3 Rad1 (B) g6 Bg7 f5 e6 d6 Nf6 0-0 Nc6 a6 b5 Qe7 Bd7 Rae8 <strong>2</strong> (W) exf5 Bxe6+ d5 g4 h3 Ne4 Nd4 Rde1 Rf3 Kh1 (B) gxf5 Bxe6 Nxd4 Nxd5 c6 Qh4 h6 Kf7 Rg8 <strong>3</strong> (W) Nxd6+ Bxd4 c3 Rxe6 Qxf5+ Kg2 g5 Rd3 (B) Nxf4+ hxg5 Rxe6 Ke7 Bxd4 <strong>4</strong> (W) Rxd4 Ne4 a4 Kf3 (B) bxa4 Qxh3+ g4+ Rh8 Rh6 Nd5 <strong>5</strong> (W) Nc5 Rd3 Qe5+ Ke2 (B) Qg2+ Kf7 a3 Rh1 Rh3 <strong>6</strong> (W) Rxh3 Kd3 Ne4 (B) gxh3 a2 Qf3+ Rd1+ Ne3 <strong>7</strong> (W) c4 Qb2 Nd2 Kd4 (B) Rxd2+ h2 0-1<br />
  A rule that a player must escape check on the first move of a turn was later introduced. Despite the above example, it would seem that White has a substantial advantage. This could be offset by limiting White's moves on the first turn. This variant has been played by a number of masters.</p>
  <p><strong>SWARM CHESS</strong> Ralph Betza (1980) Every man that can move on a player's turn is obliged to do so. (There is no penalty if a man cannot move.) Moves can be played in any order. The opposing king can be captured as well as checkmated. A player, whose king may be subject to a number of checks, must get out of check on the first move of a turn. Castling is a king move (<em>Nost-algia</em> 248). The game overwhelmingly favours White. This could be compensated for by allowing White to move, say, only six men on the first turn.</p>
  <p>[<em>Nost-algia</em> was the official organ of the defunct postal chess club <a href="https://www.chessvariants.com/nost.html" rel="nofollow noreferrer">NOST</a>, the Knights of the Square Table.]</p>
  
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Answers.Text: Battle chess is playable in mobile (under a different name). It is implement as a mobile app [Chess but all at once](https://play.google.com/store/apps/details?id=com.Jimjum.chessbaao&hl=en_US&pli=1)
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Body: <p>Imagine a chess variant where you could make 1 move for each of your pieces on the board during your turn.  There is no mate in one on the first move so far as I can see.  Also, things that would normally be checkmates would not be, as players would be able to coordinate defenses with multiple pieces.</p>
  <p>Would there be a fatal flaw in this variant?  Could it work?</p>
  
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2024-04-29T03:32:25.380Z
Comments.Text: I think I've seen this variant years ago; I can't locate it but there's a similar "swarm chess" listed in Wikipedia and explained further in this YouTube video <https://www.youtube.com/watch?v=kFhGjx5YHHs> where you *must* move each piece that has a legal move (except that the video shows White must make only 6 moves on turn 1).
Comments.UserDisplayName: Noam D. Elkies
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Comments.Text: This has some similarity.  In my version there would be no cap on the number of moves, and you would be allowed to not move a piece so long as you have at least one move.
Comments.UserDisplayName: Ben G
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Comments.CreationDate: 2024-06-27T09:58:30.427Z
Comments.Text: This is playable in mobile. Battle chess is playable under the name "Chess but all at once"
Comments.UserDisplayName: Cyriac Antony
Tags: <chess-variants>
Title: Chess Variant Idea: Every piece can move on each turn
ThreadText: # Chess Variant Idea: Every piece can move on each turn
  
  (Asked by: username_0 on 2024-04-29)
  
  Imagine a chess variant where you could make 1 move for each of your pieces on the board during your turn. There is no mate in one on the first move so far as I can see. Also, things that would normally be checkmates would not be, as players would be able to coordinate defenses with multiple pieces.
  
  Would there be a fatal flaw in this variant? Could it work?
  
  **Tags:** chess-variants
  
  > **Comments:**
  > **username_1**: I think I've seen this variant years ago; I can't locate it but there's a similar "swarm chess" listed in Wikipedia and explained further in this YouTube video <https://www.youtube.com/watch?v=kFhGjx5YHHs> where you *must* move each piece that has a legal move (except that the video shows White must make only 6 moves on turn 1).  
  > **username_0**: This has some similarity.  In my version there would be no cap on the number of moves, and you would be allowed to not move a piece so long as you have at least one move.  
  > **username_2**: This is playable in mobile. Battle chess is playable under the name "Chess but all at once"  
  
  ---
  
  ## 2 answers
  
  ### Answer by username_6 on 2024-04-30. Score: 5
  
  According to [*The Encyclopedia of Chess Variants*](https://www.chessvariants.com/books.dir/ecv.html) (**ECV**) by [David B. Pritchard](https://en.wikipedia.org/wiki/David_Pritchard_(chess_player)), chess variants based on this idea have been invented at least four times. The following descriptions are copied from **ECV**. (The names Battle Chess and Omni Chess have also been used for other chess variants. Swarm Chess was mentioned in a comment by username_1.)
  
  **BATTLE CHESS** aka **RATUSHNY'S GAME** Origins unknown; quoted in a letter by Russell Chauvenet (*Chess* Jan 1944). Each player can, but is not obliged to, move every pawn and piece once in a turn. Multiple checks are possible. Tense play, with White holding a considerable advantage.
  
  **HURRICANE CHESS** (1970s?) Every man may move once per turn. At no time during the turn may a player put himself in check. A player in check must get out of check on the first move of a turn.
  
  **OMNI CHESS** Richard Fireman and Bob Gorga (1979). Each player has the right to move any number of his men once each on a turn. Castling counts as both K. and R. moves. Multiple checks are possible. A player need only escape check at the end of a turn. One of the first games played between the inventors:  
  *White* **Richard Fireman** *Black* **Bob Gorga** **1** (W) e4 d4 Bc4 Ne2 0-0 Qd3 a3 b4 f4 Bb2 Nc3 Rad1 (B) g6 Bg7 f5 e6 d6 Nf6 0-0 Nc6 a6 b5 Qe7 Bd7 Rae8 **2** (W) exf5 Bxe6+ d5 g4 h3 Ne4 Nd4 Rde1 Rf3 Kh1 (B) gxf5 Bxe6 Nxd4 Nxd5 c6 Qh4 h6 Kf7 Rg8 **3** (W) Nxd6+ Bxd4 c3 Rxe6 Qxf5+ Kg2 g5 Rd3 (B) Nxf4+ hxg5 Rxe6 Ke7 Bxd4 **4** (W) Rxd4 Ne4 a4 Kf3 (B) bxa4 Qxh3+ g4+ Rh8 Rh6 Nd5 **5** (W) Nc5 Rd3 Qe5+ Ke2 (B) Qg2+ Kf7 a3 Rh1 Rh3 **6** (W) Rxh3 Kd3 Ne4 (B) gxh3 a2 Qf3+ Rd1+ Ne3 **7** (W) c4 Qb2 Nd2 Kd4 (B) Rxd2+ h2 0-1  
  A rule that a player must escape check on the first move of a turn was later introduced. Despite the above example, it would seem that White has a substantial advantage. This could be offset by limiting White's moves on the first turn. This variant has been played by a number of masters.
  
  **SWARM CHESS** Ralph Betza (1980) Every man that can move on a player's turn is obliged to do so. (There is no penalty if a man cannot move.) Moves can be played in any order. The opposing king can be captured as well as checkmated. A player, whose king may be subject to a number of checks, must get out of check on the first move of a turn. Castling is a king move (*Nost-algia* 248). The game overwhelmingly favours White. This could be compensated for by allowing White to move, say, only six men on the first turn.
  
  [*Nost-algia* was the official organ of the defunct postal chess club [NOST](https://www.chessvariants.com/nost.html), the Knights of the Square Table.]
  
  > **Comments:**
  > **username_2**: Battle chess is playable in mobile (under a different name). It is implement as a mobile app [Chess but all at once](https://play.google.com/store/apps/details?id=com.Jimjum.chessbaao&hl=en_US&pli=1)  
  
  ---
  
  ### Answer by username_3 on 2024-04-29. Score: 4
  
  Interesting variant, a few random thoughts.
  
  Firstly need to clarify whether all the moves must be legal in the position facing the player, or alternatively that they play a sequence. (E.g. Is 1. a2-a4 & Ra1-a3 legal?)
  
  * If the former, then an exception is required that we don't worry about being in check until all the moves have been played.
  * If the latter then need to confirm whether it is ok in an intermediate position to be in check or to check the opponent.
  
  Assuming the latter, checkmate is not impossible: each defender can only move once, but it’s certainly harder. Scholar’s mate is no longer checkmate, since Back can escape by d7–d5 Qd8-d6 Ke8-d8. But more effective is e7-e6 Ke8xf7 now the bishop guard on f7 is interrupted.
  
  Nevertheless, it appears that the game must be massively in White’s favour. I’m guessing that White has forced mate in 3.
  
  Suppose we pick k with 0
  
  Have you tried playing this game?
  
  > **Comments:**
  > **username_0**: No, I'm going to try playing it soon with a friend.  Would be interesting if there was a forced mate in N moves.  I like the purity of each piece being able to move during its turn, but the game would of course not work if there is a forced mate in N moves from that.  
  > **username_4**: Incidentally the unlimited rising k variant is solved for White; but k was > the number of pieces per side on the final position at the time. I've played kung fu chess; and I have a guess that limiting to one move per piece per turn shouldn't be a forced mate for White.  
  > **username_5**: Re the rules: You can probably just steal the rules from [progressive chess](https://www.chessvariants.com/multimove.dir/progressive.html) or another "more than one move per turn" variant.  
  
  ---
  
  