Answers.Body: <p>Revised stockfish and added this goal to win the game.</p>
  <ul>
  <li>Created 22 start opening mostly 2 plies others are 4 plies. Done carefully to minimize white advantage in the opening.</li>
  </ul>
  <pre><code>[Event &quot;?&quot;]
  [Site &quot;?&quot;]
  [Date &quot;?&quot;]
  [Round &quot;?&quot;]
  [White &quot;?&quot;]
  [Black &quot;?&quot;]
  [Result &quot;*&quot;]
  
  1.e4 c5 *
  
  [Event &quot;?&quot;]
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  [Round &quot;?&quot;]
  [White &quot;?&quot;]
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  [Result &quot;*&quot;]
  
  1.e4 e5 *
  
  [Event &quot;?&quot;]
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  [Date &quot;?&quot;]
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  [White &quot;?&quot;]
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  [Result &quot;*&quot;]
  
  1.e4 e5 2.Nf3 Nc6 *
  
  [Event &quot;?&quot;]
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  [White &quot;?&quot;]
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  [Result &quot;*&quot;]
  
  1.e4 e6 *
  
  [Event &quot;?&quot;]
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  [White &quot;?&quot;]
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  [Result &quot;*&quot;]
  
  1.e4 Nf6 *
  
  [Event &quot;?&quot;]
  [Site &quot;?&quot;]
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  [White &quot;?&quot;]
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  [Result &quot;*&quot;]
  
  1.e4 Nc6 *
  
  [Event &quot;?&quot;]
  [Site &quot;?&quot;]
  [Date &quot;?&quot;]
  [Round &quot;?&quot;]
  [White &quot;?&quot;]
  [Black &quot;?&quot;]
  [Result &quot;*&quot;]
  
  1.e4 Nc6 2.Nc3 e5 *
  
  [Event &quot;?&quot;]
  [Site &quot;?&quot;]
  [Date &quot;?&quot;]
  [Round &quot;?&quot;]
  [White &quot;?&quot;]
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  [Result &quot;*&quot;]
  
  1.e4 d5 *
  
  [Event &quot;?&quot;]
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  [Round &quot;?&quot;]
  [White &quot;?&quot;]
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  [Result &quot;*&quot;]
  
  1.d4 d5 *
  
  [Event &quot;?&quot;]
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  [White &quot;?&quot;]
  [Black &quot;?&quot;]
  [Result &quot;*&quot;]
  
  1.d4 d5 2.Bf4 Bf5 *
  
  [Event &quot;?&quot;]
  [Site &quot;?&quot;]
  [Date &quot;?&quot;]
  [Round &quot;?&quot;]
  [White &quot;?&quot;]
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  [Result &quot;*&quot;]
  
  1.d4 Nf6 *
  
  [Event &quot;?&quot;]
  [Site &quot;?&quot;]
  [Date &quot;?&quot;]
  [Round &quot;?&quot;]
  [White &quot;?&quot;]
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  [Result &quot;*&quot;]
  
  1.c4 e5 *
  
  [Event &quot;?&quot;]
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  [White &quot;?&quot;]
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  [Result &quot;*&quot;]
  
  1.c4 c5 *
  
  [Event &quot;?&quot;]
  [Site &quot;?&quot;]
  [Date &quot;?&quot;]
  [Round &quot;?&quot;]
  [White &quot;?&quot;]
  [Black &quot;?&quot;]
  [Result &quot;*&quot;]
  
  1.c4 Nf6 *
  
  [Event &quot;?&quot;]
  [Site &quot;?&quot;]
  [Date &quot;?&quot;]
  [Round &quot;?&quot;]
  [White &quot;?&quot;]
  [Black &quot;?&quot;]
  [Result &quot;*&quot;]
  
  1.c4 d6 *
  
  [Event &quot;?&quot;]
  [Site &quot;?&quot;]
  [Date &quot;?&quot;]
  [Round &quot;?&quot;]
  [White &quot;?&quot;]
  [Black &quot;?&quot;]
  [Result &quot;*&quot;]
  
  1.c4 g6 *
  
  [Event &quot;?&quot;]
  [Site &quot;?&quot;]
  [Date &quot;?&quot;]
  [Round &quot;?&quot;]
  [White &quot;?&quot;]
  [Black &quot;?&quot;]
  [Result &quot;*&quot;]
  
  1.c4 Nc6 *
  
  [Event &quot;?&quot;]
  [Site &quot;?&quot;]
  [Date &quot;?&quot;]
  [Round &quot;?&quot;]
  [White &quot;?&quot;]
  [Black &quot;?&quot;]
  [Result &quot;*&quot;]
  
  1.Nf3 d5 *
  
  [Event &quot;?&quot;]
  [Site &quot;?&quot;]
  [Date &quot;?&quot;]
  [Round &quot;?&quot;]
  [White &quot;?&quot;]
  [Black &quot;?&quot;]
  [Result &quot;*&quot;]
  
  1.Nf3 Nf6 *
  
  [Event &quot;?&quot;]
  [Site &quot;?&quot;]
  [Date &quot;?&quot;]
  [Round &quot;?&quot;]
  [White &quot;?&quot;]
  [Black &quot;?&quot;]
  [Result &quot;*&quot;]
  
  1.Nf3 c5 *
  
  [Event &quot;?&quot;]
  [Site &quot;?&quot;]
  [Date &quot;?&quot;]
  [Round &quot;?&quot;]
  [White &quot;?&quot;]
  [Black &quot;?&quot;]
  [Result &quot;*&quot;]
  
  1.Nf3 e6 *
  
  [Event &quot;?&quot;]
  [Site &quot;?&quot;]
  [Date &quot;?&quot;]
  [Round &quot;?&quot;]
  [White &quot;?&quot;]
  [Black &quot;?&quot;]
  [Result &quot;*&quot;]
  
  1.Nf3 d5 2.d4 Bf5 *
  
  </code></pre>
  <ul>
  <li>Run a match at TC 3m+1s</li>
  </ul>
  <h4>Result</h4>
  <pre><code>Score of sfbackrank_e2 vs sfbackrank_e1: 8 - 13 - 1 [0.386]
  ...      sfbackrank_e2 playing White: 5 - 5 - 1  [0.500] 11
  ...      sfbackrank_e2 playing Black: 3 - 8 - 0  [0.273] 11
  ...      White vs Black: 13 - 8 - 1  [0.614] 22
  Elo difference: -80.4 +/- 156.7, LOS: 13.8 %, DrawRatio: 4.5 %
  22 of 22 games finished.
  </code></pre>
  <p>sfbackrank_e2 and sfbackrank_e1 are the same engine. The white side won.</p>
  <pre><code>White vs Black: 13 - 8 - 1  [0.614] 22
  </code></pre>
  <h4>Sample games</h4>
  <p><a href="https://lichess.org/Ab5lGE1w" rel="nofollow noreferrer">https://lichess.org/Ab5lGE1w</a><br />
  <a href="https://lichess.org/4VdHGQkm" rel="nofollow noreferrer">https://lichess.org/4VdHGQkm</a><br />
  <a href="https://lichess.org/b8xxzvjZ" rel="nofollow noreferrer">https://lichess.org/b8xxzvjZ</a><br />
  <a href="https://lichess.org/IVpjazCV" rel="nofollow noreferrer">https://lichess.org/IVpjazCV</a><br />
  <a href="https://lichess.org/gwwYdwCA" rel="nofollow noreferrer">https://lichess.org/gwwYdwCA</a><br />
  <a href="https://lichess.org/QdiEcpyK" rel="nofollow noreferrer">https://lichess.org/QdiEcpyK</a><br />
  <a href="https://lichess.org/GmCdzkz8" rel="nofollow noreferrer">https://lichess.org/GmCdzkz8</a><br />
  <a href="https://lichess.org/cDR66Vuq" rel="nofollow noreferrer">https://lichess.org/cDR66Vuq</a><br />
  <a href="https://lichess.org/5Fc6G9MC" rel="nofollow noreferrer">https://lichess.org/5Fc6G9MC</a></p>
  
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2022-01-27T03:30:24.663Z
Answers.Text: I checked several of the example games and don't see any actual wins. Are you using some kind of adjudication rule? If so, what is it?
Answers.UserDisplayName: Allure
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2022-01-27T05:24:10.650Z
Answers.Text: When 2 engines agreed that the last 2 successive moves have scores of 900 cp or more in favor of one engine then game is adjudicated. I use cutechess-gui.
Answers.UserDisplayName: ferdy
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2022-01-25T18:17:27.263Z
Answers.LastActivityDate: 2022-01-25T18:17:27.263Z
Answers.UserDisplayName: ferdy
Body: <p>Consider a chess variant in which normal chess rules apply, with one exception. The player that is able to bring a piece or a pawn onto the opponent’s back rank, which would be the 8th rank for White and the 1st rank for Black, wins immediately. The move has to be legal and it ends the game, even if the opponent could mate on the next move.</p>
  <p>On Liches some chess variants like King of the Hill, Atomic, and Three-Check can be analyzed. Can I easily adjust Stockfish or another chess program such that this new rule applies? Would White have a big advantage in this game? Or can we even show that White has a winning strategy?</p>
  
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2020-08-25T09:06:55.623Z
Comments.Text: I created an engine that plays a related variant. With no kings, the task is to move a pawn to the final rank. You can play against the engine  https://www.apronus.com/chess/puzzle/?p=0rnbq1bnrXppppppppX8X8X8X8XPPPPPPPPXRNBQ1BNR_w_-_-_0_1&N=0&w=&h=%3Ch3%3EPlay%20against%20computer.%3C%2Fh3%3E%3Ch5%3EEndgame%20Chess%20Variant.%20Promotion%20wins.%20Having%20no%20moves%20loses.%3C%2Fh5%3E
Comments.UserDisplayName: MichalRyszardWojcik
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2021-08-24T19:03:37.943Z
Comments.Text: Sounds like a fun variation. Simply tweaking Stockfish's evaluation function so that it evaluates such positions as being mates would probably lead to decent play, but deeper changes to the evaluation function would probably be needed for optimal play. Deep learning approaches would be easier to modify.
Comments.UserDisplayName: John Coleman
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2021-12-15T16:12:28.043Z
Comments.Text: So if you capture all of your opponents pawns, is the worst you can do a draw or can they still win with checkmate? Can you promote a pawn if in check?
Comments.UserDisplayName: user70889
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2021-12-15T18:07:59.053Z
Comments.Text: @MichalRyszardWojcik: Could you also program the variant only with pawns? That's a standard fun game in kid training.
Comments.UserDisplayName: Hauke Reddmann
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2021-12-17T14:11:58.043Z
Comments.Text: @HaukeReddmann https://www.apronus.com/chess/puzzle/?p=08XppppppppX8X8X8X8XPPPPPPPPX8_w_-_-_0_1&N=0&w=&h=%3Ch3%3EPlay%20against%20computer.%3C%2Fh3%3E%3Ch5%3EPawn%20Wars.%20Promotion%20wins.%20Having%20no%20moves%20loses.%20No%20draw.%3C%2Fh5%3E -- Pawn Wars. Promotion wins. Having no moves loses. No draw. On my editor you can set up any position with or without kings and create a link to share.
Comments.UserDisplayName: MichalRyszardWojcik
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2021-12-17T19:33:37.783Z
Comments.Text: @MichalRyszardWojcik: THX! Normally I don't even need the editor, since the URL says all :-)
Comments.UserDisplayName: Hauke Reddmann
Tags: <software><chess-variants><solving>
Title: How big is the advantage for white in the "back-rank-game"?
ThreadText: # How big is the advantage for white in the "back-rank-game"?
  
  (Asked by: username_0 on 2020-08-24)
  
  Consider a chess variant in which normal chess rules apply, with one exception. The player that is able to bring a piece or a pawn onto the opponent’s back rank, which would be the 8th rank for White and the 1st rank for Black, wins immediately. The move has to be legal and it ends the game, even if the opponent could mate on the next move.
  
  On Liches some chess variants like King of the Hill, Atomic, and Three-Check can be analyzed. Can I easily adjust Stockfish or another chess program such that this new rule applies? Would White have a big advantage in this game? Or can we even show that White has a winning strategy?
  
  **Tags:** software, chess-variants, solving
  
  > **Comments:**
  > **username_1**: I created an engine that plays a related variant. With no kings, the task is to move a pawn to the final rank. You can play against the engine  https://www.apronus.com/chess/puzzle/?p=0rnbq1bnrXppppppppX8X8X8X8XPPPPPPPPXRNBQ1BNR_w_-_-_0_1&N=0&w=&h=%3Ch3%3EPlay%20against%20computer.%3C%2Fh3%3E%3Ch5%3EEndgame%20Chess%20Variant.%20Promotion%20wins.%20Having%20no%20moves%20loses.%3C%2Fh5%3E  
  > **username_2**: Sounds like a fun variation. Simply tweaking Stockfish's evaluation function so that it evaluates such positions as being mates would probably lead to decent play, but deeper changes to the evaluation function would probably be needed for optimal play. Deep learning approaches would be easier to modify.  
  > **username_3**: So if you capture all of your opponents pawns, is the worst you can do a draw or can they still win with checkmate? Can you promote a pawn if in check?  
  > **username_4**: @username_1: Could you also program the variant only with pawns? That's a standard fun game in kid training.  
  > **username_1**: @HaukeReddmann https://www.apronus.com/chess/puzzle/?p=08XppppppppX8X8X8X8XPPPPPPPPX8_w_-_-_0_1&N=0&w=&h=%3Ch3%3EPlay%20against%20computer.%3C%2Fh3%3E%3Ch5%3EPawn%20Wars.%20Promotion%20wins.%20Having%20no%20moves%20loses.%20No%20draw.%3C%2Fh5%3E -- Pawn Wars. Promotion wins. Having no moves loses. No draw. On my editor you can set up any position with or without kings and create a link to share.  
  > **username_4**: @username_1: THX! Normally I don't even need the editor, since the URL says all :-)  
  
  ---
  
  ## 1 answers
  
  ### Answer by username_5 on 2022-01-25. Score: 3
  
  Revised stockfish and added this goal to win the game.
  
  Created 22 start opening mostly 2 plies others are 4 plies. Done carefully to minimize white advantage in the opening.
  
  [Event "?"]
  [Site "?"]
  [Date "?"]
  [Round "?"]
  [White "?"]
  [Black "?"]
  [Result "*"]
  
  1.e4 c5 *
  
  [Event "?"]
  [Site "?"]
  [Date "?"]
  [Round "?"]
  [White "?"]
  [Black "?"]
  [Result "*"]
  
  1.e4 e5 *
  
  [Event "?"]
  [Site "?"]
  [Date "?"]
  [Round "?"]
  [White "?"]
  [Black "?"]
  [Result "*"]
  
  1.e4 e5 2.Nf3 Nc6 *
  
  [Event "?"]
  [Site "?"]
  [Date "?"]
  [Round "?"]
  [White "?"]
  [Black "?"]
  [Result "*"]
  
  1.e4 e6 *
  
  [Event "?"]
  [Site "?"]
  [Date "?"]
  [Round "?"]
  [White "?"]
  [Black "?"]
  [Result "*"]
  
  1.e4 Nf6 *
  
  [Event "?"]
  [Site "?"]
  [Date "?"]
  [Round "?"]
  [White "?"]
  [Black "?"]
  [Result "*"]
  
  1.e4 Nc6 *
  
  [Event "?"]
  [Site "?"]
  [Date "?"]
  [Round "?"]
  [White "?"]
  [Black "?"]
  [Result "*"]
  
  1.e4 Nc6 2.Nc3 e5 *
  
  [Event "?"]
  [Site "?"]
  [Date "?"]
  [Round "?"]
  [White "?"]
  [Black "?"]
  [Result "*"]
  
  1.e4 d5 *
  
  [Event "?"]
  [Site "?"]
  [Date "?"]
  [Round "?"]
  [White "?"]
  [Black "?"]
  [Result "*"]
  
  1.d4 d5 *
  
  [Event "?"]
  [Site "?"]
  [Date "?"]
  [Round "?"]
  [White "?"]
  [Black "?"]
  [Result "*"]
  
  1.d4 d5 2.Bf4 Bf5 *
  
  [Event "?"]
  [Site "?"]
  [Date "?"]
  [Round "?"]
  [White "?"]
  [Black "?"]
  [Result "*"]
  
  1.d4 Nf6 *
  
  [Event "?"]
  [Site "?"]
  [Date "?"]
  [Round "?"]
  [White "?"]
  [Black "?"]
  [Result "*"]
  
  1.c4 e5 *
  
  [Event "?"]
  [Site "?"]
  [Date "?"]
  [Round "?"]
  [White "?"]
  [Black "?"]
  [Result "*"]
  
  1.c4 c5 *
  
  [Event "?"]
  [Site "?"]
  [Date "?"]
  [Round "?"]
  [White "?"]
  [Black "?"]
  [Result "*"]
  
  1.c4 Nf6 *
  
  [Event "?"]
  [Site "?"]
  [Date "?"]
  [Round "?"]
  [White "?"]
  [Black "?"]
  [Result "*"]
  
  1.c4 d6 *
  
  [Event "?"]
  [Site "?"]
  [Date "?"]
  [Round "?"]
  [White "?"]
  [Black "?"]
  [Result "*"]
  
  1.c4 g6 *
  
  [Event "?"]
  [Site "?"]
  [Date "?"]
  [Round "?"]
  [White "?"]
  [Black "?"]
  [Result "*"]
  
  1.c4 Nc6 *
  
  [Event "?"]
  [Site "?"]
  [Date "?"]
  [Round "?"]
  [White "?"]
  [Black "?"]
  [Result "*"]
  
  1.Nf3 d5 *
  
  [Event "?"]
  [Site "?"]
  [Date "?"]
  [Round "?"]
  [White "?"]
  [Black "?"]
  [Result "*"]
  
  1.Nf3 Nf6 *
  
  [Event "?"]
  [Site "?"]
  [Date "?"]
  [Round "?"]
  [White "?"]
  [Black "?"]
  [Result "*"]
  
  1.Nf3 c5 *
  
  [Event "?"]
  [Site "?"]
  [Date "?"]
  [Round "?"]
  [White "?"]
  [Black "?"]
  [Result "*"]
  
  1.Nf3 e6 *
  
  [Event "?"]
  [Site "?"]
  [Date "?"]
  [Round "?"]
  [White "?"]
  [Black "?"]
  [Result "*"]
  
  1.Nf3 d5 2.d4 Bf5 *
  
  
  
  Run a match at TC 3m+1s
  
  Result
  Score of sfbackrank_e2 vs sfbackrank_e1: 8 - 13 - 1 [0.386]
  ...      sfbackrank_e2 playing White: 5 - 5 - 1  [0.500] 11
  ...      sfbackrank_e2 playing Black: 3 - 8 - 0  [0.273] 11
  ...      White vs Black: 13 - 8 - 1  [0.614] 22
  Elo difference: -80.4 +/- 156.7, LOS: 13.8 %, DrawRatio: 4.5 %
  22 of 22 games finished.
  
  sfbackrank_e2 and sfbackrank_e1 are the same engine. The white side won.
  White vs Black: 13 - 8 - 1  [0.614] 22
  
  Sample games
  https://lichess.org/Ab5lGE1w
  https://lichess.org/4VdHGQkm
  https://lichess.org/b8xxzvjZ
  https://lichess.org/IVpjazCV
  https://lichess.org/gwwYdwCA
  https://lichess.org/QdiEcpyK
  https://lichess.org/GmCdzkz8
  https://lichess.org/cDR66Vuq
  https://lichess.org/5Fc6G9MC
  
  > **Comments:**
  > **username_6**: I checked several of the example games and don't see any actual wins. Are you using some kind of adjudication rule? If so, what is it?  
  > **username_5**: When 2 engines agreed that the last 2 successive moves have scores of 900 cp or more in favor of one engine then game is adjudicated. I use cutechess-gui.  
  
  ---
  
  