Answers.Body: <p>Just one piece fewer, but how about:</p>
  <pre><code>[FEN &quot;5brr/4p1pq/4P1pk/4N1p1/6P1/6PK/6PP/8 w - - 0 1&quot;]
  
  1.Nd7= {Black stalemated} (1.Nf7#) (1.Nxg6 Kxg6#) (1.Nxg6 Qxg6= {White stalemated})
  </code></pre>
  
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2022-04-10T06:55:49.803Z
Answers.Text: Valid! (1.N~=, 1.Nf7#, 1.Nxg6 Kxg6#, 1.Nxg6 Qxg6=)
Answers.UserDisplayName: Hauke Reddmann
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2022-04-11T07:31:52.680Z
Answers.Text: Accepted for now, although maybe it still can be economized. E.g. consider the far lighter Kh3 Qb4 Pg2 - Kh5 Ph6 Pg6 Pg5 Ph4 Pg3. Almost! (Qg4#, Qa5=, Qxh4 gxh4=, Qa6 g4#, but after Qf4 Black can choose g4+, game over in 1.5 instead of 1. Too bad!)
Answers.UserDisplayName: Hauke Reddmann
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2022-04-12T08:19:59.727Z
Answers.Text: Can an acceptance be withdrawn? This still seems early days for this challenge
Answers.UserDisplayName: Laska
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2022-04-13T16:02:28.863Z
Answers.Text: @Laska The OP can always change their mind about accepted answer
Answers.UserDisplayName: Brian Towers
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2022-04-09T18:51:29.180Z
Answers.LastActivityDate: 2022-04-13T16:01:25.013Z
Answers.LastEditDate: 2022-04-13T16:01:25.013Z
Answers.UserDisplayName: James Martin
Answers.Body: <p>I knew it! 13 pieces:</p>
  <pre><code>[FEN &quot;8/6p1/6P1/6PB/6P1/4p1pQ/4Pp1p/5K1k w - - 0 0&quot;]
  </code></pre>
  <p>1.Qg2#/1.Qxg3=/1.Qh4 g2#/1.Qxh2+ K,gxh2=</p>
  <p>Note that 5 pieces just stand around against 1.Qg4, which also ends the game, but in 1.5 moves - <em>still</em> too bad!</p>
  
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2022-04-11T10:03:05.363Z
Answers.Text: Note: If you drop the "*any* move ends..." condition, it is possible with a mere 5 pieces: https://www.yacpdb.org/#407710
Answers.UserDisplayName: Hauke Reddmann
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2022-04-11T10:52:54.893Z
Answers.Text: I like it! Nice that white has just four options, each of which leads to a different outcome.
Answers.UserDisplayName: James Martin
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2022-04-11T17:49:00.710Z
Answers.Text: @DialFrost: BTW, your deleted solution is perfectly legit, if only a bit illegal. :-)
Answers.UserDisplayName: Hauke Reddmann
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2022-04-11T09:21:08.693Z
Answers.LastActivityDate: 2022-04-11T09:21:08.693Z
Answers.UserDisplayName: Hauke Reddmann
Body: <p>Compose a position where</p>
  <ol>
  <li>It's White to move</li>
  <li>White can deliver checkmate or stalemate in 1 move</li>
  <li>Or if they make a different move, then Black can deliver checkmate or stalemate in one 1 move</li>
  </ol>
  <p>I needed 6 white pieces and 11 black pieces. Beat me!</p>
  <p>Toned down example for understanding:</p>
  <pre><code>[FEN &quot;7k/7P/7K/6BP/8/8/8/8 w - - 0 0&quot;]
  </code></pre>
  <p>After the next White move, Black is either mated or stalemated, depending on if White plays Bf6 or not. (This does not meet the 3rd requirement).</p>
  
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2022-04-09T13:40:51.977Z
Comments.Text: Sry but wat does 6w+11b mean?
Comments.UserDisplayName: DialFrost
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2022-04-09T13:48:21.943Z
Comments.Text: 6 white pieces and 11 black pieces?
Comments.UserDisplayName: Glorfindel
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2022-04-09T14:15:52.017Z
Comments.Text: How is white getting stalemated or checkmated possible in your above example? Plus, black can't even move if white plays Bf6#. But in your condition, it says *Latest after Black's answer it's game over*.
Comments.UserDisplayName: Abhyuday Vaish
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2022-04-10T06:51:15.320Z
Comments.Text: @AbhyudayVaish: "Toned down example" - with only two possible outcomes. NO example for the wanted position!
Comments.UserDisplayName: Hauke Reddmann
Tags: <problems><checkmate><stalemate>
Title: Puzzle: Forced game end in at most two halfmoves
ThreadText: # Puzzle: Forced game end in at most two halfmoves
  
  (Asked by: username_0 on 2022-04-09)
  
  Compose a position where
  
  1. It's White to move
  2. White can deliver checkmate or stalemate in 1 move
  3. Or if they make a different move, then Black can deliver checkmate or stalemate in one 1 move
  
  I needed 6 white pieces and 11 black pieces. Beat me!
  
  Toned down example for understanding:
  
  ```
  [FEN "7k/7P/7K/6BP/8/8/8/8 w - - 0 0"]
  
  ```
  
  After the next White move, Black is either mated or stalemated, depending on if White plays Bf6 or not. (This does not meet the 3rd requirement).
  
  **Tags:** problems, checkmate, stalemate
  
  > **Comments:**
  > **username_1**: Sry but wat does 6w+11b mean?  
  > **username_2**: 6 white pieces and 11 black pieces?  
  > **username_3**: How is white getting stalemated or checkmated possible in your above example? Plus, black can't even move if white plays Bf6#. But in your condition, it says *Latest after Black's answer it's game over*.  
  > **username_0**: @username_3: "Toned down example" - with only two possible outcomes. NO example for the wanted position!  
  
  ---
  
  ## 2 answers
  
  ### Answer by username_4 on 2022-04-09. Score: 2 | Accepted answer
  
  Just one piece fewer, but how about:
  
  ```
  [FEN "5brr/4p1pq/4P1pk/4N1p1/6P1/6PK/6PP/8 w - - 0 1"]
  
  1.Nd7= {Black stalemated} (1.Nf7#) (1.Nxg6 Kxg6#) (1.Nxg6 Qxg6= {White stalemated})
  
  ```
  
  > **Comments:**
  > **username_0**: Valid! (1.N~=, 1.Nf7#, 1.Nxg6 Kxg6#, 1.Nxg6 Qxg6=)  
  > **username_0**: Accepted for now, although maybe it still can be economized. E.g. consider the far lighter Kh3 Qb4 Pg2 - Kh5 Ph6 Pg6 Pg5 Ph4 Pg3. Almost! (Qg4#, Qa5=, Qxh4 gxh4=, Qa6 g4#, but after Qf4 Black can choose g4+, game over in 1.5 instead of 1. Too bad!)  
  > **username_5**: Can an acceptance be withdrawn? This still seems early days for this challenge  
  > **username_6**: @username_5 The OP can always change their mind about accepted answer  
  
  ---
  
  ### Answer by username_0 on 2022-04-11. Score: 2
  
  I knew it! 13 pieces:
  
  ```
  [FEN "8/6p1/6P1/6PB/6P1/4p1pQ/4Pp1p/5K1k w - - 0 0"]
  
  ```
  
  1.Qg2#/1.Qxg3=/1.Qh4 g2#/1.Qxh2+ K,gxh2=
  
  Note that 5 pieces just stand around against 1.Qg4, which also ends the game, but in 1.5 moves - *still* too bad!
  
  > **Comments:**
  > **username_0**: Note: If you drop the "*any* move ends..." condition, it is possible with a mere 5 pieces: https://www.yacpdb.org/#407710  
  > **username_4**: I like it! Nice that white has just four options, each of which leads to a different outcome.  
  > **username_0**: @username_1: BTW, your deleted solution is perfectly legit, if only a bit illegal. :-)  
  
  ---
  
  