Answers.Body: <p>The first surprise is that <strong>if we change the starting position to have mirror symmetry (like western chess) instead of rotational symmetry (like Japanese chess) we get a drawn position</strong> in which any lion move is losing.</p>
  
  <pre><code>1. setup S/elg/-c-/-C-/ELG/
  1. show board
    ABC 
   +---+
  1|elg| 
  2| c |
  3| C |
  4|ELG| *
   +---+
  1. show lines
  Cb3xb2 : 0     (50.00%)
  Gc4-c3 : 0     (50.00%)
  Lb4-c3 : #-46  ( 0.00%)
  Lb4-a3 : #-46  ( 0.00%)
  </code></pre>
  
  <p>Giraffes and elephants are freely exchanged in winning lines, so they must be very close in value. Still, elephants (like bishops in western chess) suffer from being restricted to half of the squares, which probably explains that <strong>giraffes versus elephants is a win for the giraffes</strong>.</p>
  
  <pre><code>1. setup S/ele/-c-/-C-/GLG/
  1. show board
    ABC 
   +---+
  1|ele| 
  2| c |
  3| C |
  4|GLG| *
   +---+
  1. show lines
  Lb4-c3 : #25   (50.00%)
  Lb4-a3 : #25   (50.00%)
  Cb3xb2 : #53   ( 0.00%)
  Gc4-c3 : #53   ( 0.00%)
  Ga4-a3 : #53   ( 0.00%)
  1. setup S/glg/-c-/-C-/ELE/
  1. show board
    ABC 
   +---+
  1|glg| 
  2| c |
  3| C |
  4|ELE| *
   +---+
  1. show lines
  Lb4-c3 : #-32  (50.00%)
  Lb4-a3 : #-32  (50.00%)
  Cb3xb2 : #-24  ( 0.00%)
  </code></pre>
  
  <p>Or is it?</p>
  
  <pre><code>1. setup S/lee/-c-/-C-/GGL/
  1. show board
    ABC 
   +---+
  1|lee| 
  2| c |
  3| C |
  4|GGL| *
   +---+
  1. show lines
  Ga4-a3 : 0     (50.00%)
  Lc4-c3 : 0     (50.00%)
  Cb3xb2 : #-62  ( 0.00%)
  1. setup S/eel/-c-/-C-/GGL/
  1. show board
    ABC 
   +---+
  1|eel| 
  2| c |
  3| C |
  4|GGL| *
   +---+
  1. show lines
  Ga4-a3 : 0     (50.00%)
  Lc4-c3 : 0     (50.00%)
  Cb3xb2 : #-58  ( 0.00%)
  </code></pre>
  
  <p><strong>Starting giraffes draw</strong>, but beware of chick fights...</p>
  
  <pre><code>1. setup S/lgg/-c-/-C-/EEL/ 
  1. show board
    ABC 
   +---+
  1|lgg| 
  2| c |
  3| C |
  4|EEL| *
   +---+
  1. show lines
  Cb3xb2 : 0     (33.33%)
  Eb4-c3 : 0     (33.33%)
  Eb4-a3 : 0     (33.33%)
  Lc4-c3 : #-48  ( 0.00%)
  1. setup S/ggl/-c-/-C-/EEL/
  1. show board
    ABC 
   +---+
  1|ggl| 
  2| c |
  3| C |
  4|EEL| *
   +---+
  1. show lines
  Cb3xb2 : 0     (33.33%)
  Eb4-c3 : 0     (33.33%)
  Eb4-a3 : 0     (33.33%)
  Lc4-c3 : #-50  ( 0.00%)
  </code></pre>
  
  <p>...and <strong>starting elephants also draw</strong>, but beware of lion moves.</p>
  
  <p>What about side lions in the standard position?</p>
  
  <pre><code>1. setup S/lge/-c-/-C-/EGL/
  1. show board
    ABC 
   +---+
  1|lge| 
  2| c |
  3| C |
  4|EGL| *
   +---+
  1. show lines
  Cb3xb2 : 0     (50.00%)
  Lc4-c3 : 0     (50.00%)
  1. setup S/egl/-c-/-C-/EGL/
  1. show board
    ABC 
   +---+
  1|egl| 
  2| c |
  3| C |
  4|EGL| *
   +---+
  1. show lines
  Cb3xb2 : 0     (50.00%)
  Lc4-c3 : 0     (50.00%)
  </code></pre>
  
  <p><strong>Central giraffe with lion to the side is a draw</strong>.</p>
  
  <pre><code>1. setup S/leg/-c-/-C-/GEL/
  1. show board
    ABC 
   +---+
  1|leg| 
  2| c |
  3| C |
  4|GEL| *
   +---+
  1. show lines
  Eb4-a3 : #65   (100.00%)
  Cb3xb2 : 0     ( 0.00%)
  Ga4-a3 : 0     ( 0.00%)
  Eb4-c3 : 0     ( 0.00%)
  Lc4-c3 : #-44  ( 0.00%)
  1. setup S/gel/-c-/-C-/GEL/
  1. show board
    ABC 
   +---+
  1|gel| 
  2| c |
  3| C |
  4|GEL| *
   +---+
  1. show lines
  Cb3xb2 : #51   (99.94%)
  Eb4-c3 : #65   ( 0.06%)
  Ga4-a3 : 0     ( 0.00%)
  Eb4-a3 : #-64  ( 0.00%)
  Lc4-c3 : #-52  ( 0.00%)
  </code></pre>
  
  <p>It is a <strong>win if the elephant is in the middle</strong>. Notice that moving the elephant towards the enemy lion is winning in both positions and moving the lion forward is losing, but in the mirror-symmetric case, chick fight is also winning and elephant towards the other side is losing. At least in this case shogi is more drawish than western chess!</p>
  
  <p>In summary, it seems that trébuchets are quite rare (we did not find any), and most starting positions are draws with the occasional win for the starting player or loss for positions with an obvious weakness.</p>
  
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2019-01-13T09:02:49.987Z
Answers.LastActivityDate: 2019-01-13T10:04:31.217Z
Answers.LastEditDate: 2019-01-13T10:04:31.217Z
Answers.UserDisplayName: hkBst
Body: <p>In <a href="https://en.wikipedia.org/wiki/D%C5%8Dbutsu_shogi" rel="nofollow noreferrer">dobutsu shogi</a>, the usual starting position is a <a href="https://en.wikipedia.org/wiki/Zugzwang#Tr%C3%A9buchet" rel="nofollow noreferrer"><em>trébuchet</em> or <em>full-point mutual zugzwang</em></a> position, but other likely (starting) positions can have a completely different value.</p>
  
  <p>If we arrange the pieces in a different way but still mostly on the back rank and mostly on the board, are most of those positions also trébuchets or do they share another commonality?</p>
  
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2019-04-10T09:58:29.593Z
Comments.Text: @RewanDemontay, my own answer suffers from many limitations, so I am confident that much better answers are possible.
Comments.UserDisplayName: hkBst
Tags: <chess-variants><shogi>
Title: What is the value of most starting positions in dobutsu shogi?
ThreadText: # What is the value of most starting positions in dobutsu shogi?
  
  (Asked by: username_0 on 2019-01-13)
  
  In [dobutsu shogi](https://en.wikipedia.org/wiki/D%C5%8Dbutsu_shogi), the usual starting position is a [*trébuchet* or *full-point mutual zugzwang*](https://en.wikipedia.org/wiki/Zugzwang#Tr%C3%A9buchet) position, but other likely (starting) positions can have a completely different value.
  
  If we arrange the pieces in a different way but still mostly on the back rank and mostly on the board, are most of those positions also trébuchets or do they share another commonality?
  
  **Tags:** chess-variants, shogi
  
  > **Comments:**
  > **username_0**: @RewanDemontay, my own answer suffers from many limitations, so I am confident that much better answers are possible.  
  
  ---
  
  ## 1 answers
  
  ### Answer by username_0 on 2019-01-13. Score: 3
  
  The first surprise is that if we change the starting position to have mirror symmetry (like western chess) instead of rotational symmetry (like Japanese chess) we get a drawn position in which any lion move is losing.
  1. setup S/elg/-c-/-C-/ELG/
  1. show board
    ABC 
   +---+
  1|elg| 
  2| c |
  3| C |
  4|ELG| *
   +---+
  1. show lines
  Cb3xb2 : 0     (50.00%)
  Gc4-c3 : 0     (50.00%)
  Lb4-c3 : #-46  ( 0.00%)
  Lb4-a3 : #-46  ( 0.00%)
  
  Giraffes and elephants are freely exchanged in winning lines, so they must be very close in value. Still, elephants (like bishops in western chess) suffer from being restricted to half of the squares, which probably explains that giraffes versus elephants is a win for the giraffes.
  1. setup S/ele/-c-/-C-/GLG/
  1. show board
    ABC 
   +---+
  1|ele| 
  2| c |
  3| C |
  4|GLG| *
   +---+
  1. show lines
  Lb4-c3 : #25   (50.00%)
  Lb4-a3 : #25   (50.00%)
  Cb3xb2 : #53   ( 0.00%)
  Gc4-c3 : #53   ( 0.00%)
  Ga4-a3 : #53   ( 0.00%)
  1. setup S/glg/-c-/-C-/ELE/
  1. show board
    ABC 
   +---+
  1|glg| 
  2| c |
  3| C |
  4|ELE| *
   +---+
  1. show lines
  Lb4-c3 : #-32  (50.00%)
  Lb4-a3 : #-32  (50.00%)
  Cb3xb2 : #-24  ( 0.00%)
  
  Or is it?
  1. setup S/lee/-c-/-C-/GGL/
  1. show board
    ABC 
   +---+
  1|lee| 
  2| c |
  3| C |
  4|GGL| *
   +---+
  1. show lines
  Ga4-a3 : 0     (50.00%)
  Lc4-c3 : 0     (50.00%)
  Cb3xb2 : #-62  ( 0.00%)
  1. setup S/eel/-c-/-C-/GGL/
  1. show board
    ABC 
   +---+
  1|eel| 
  2| c |
  3| C |
  4|GGL| *
   +---+
  1. show lines
  Ga4-a3 : 0     (50.00%)
  Lc4-c3 : 0     (50.00%)
  Cb3xb2 : #-58  ( 0.00%)
  
  Starting giraffes draw, but beware of chick fights...
  1. setup S/lgg/-c-/-C-/EEL/ 
  1. show board
    ABC 
   +---+
  1|lgg| 
  2| c |
  3| C |
  4|EEL| *
   +---+
  1. show lines
  Cb3xb2 : 0     (33.33%)
  Eb4-c3 : 0     (33.33%)
  Eb4-a3 : 0     (33.33%)
  Lc4-c3 : #-48  ( 0.00%)
  1. setup S/ggl/-c-/-C-/EEL/
  1. show board
    ABC 
   +---+
  1|ggl| 
  2| c |
  3| C |
  4|EEL| *
   +---+
  1. show lines
  Cb3xb2 : 0     (33.33%)
  Eb4-c3 : 0     (33.33%)
  Eb4-a3 : 0     (33.33%)
  Lc4-c3 : #-50  ( 0.00%)
  
  ...and starting elephants also draw, but beware of lion moves.
  What about side lions in the standard position?
  1. setup S/lge/-c-/-C-/EGL/
  1. show board
    ABC 
   +---+
  1|lge| 
  2| c |
  3| C |
  4|EGL| *
   +---+
  1. show lines
  Cb3xb2 : 0     (50.00%)
  Lc4-c3 : 0     (50.00%)
  1. setup S/egl/-c-/-C-/EGL/
  1. show board
    ABC 
   +---+
  1|egl| 
  2| c |
  3| C |
  4|EGL| *
   +---+
  1. show lines
  Cb3xb2 : 0     (50.00%)
  Lc4-c3 : 0     (50.00%)
  
  Central giraffe with lion to the side is a draw.
  1. setup S/leg/-c-/-C-/GEL/
  1. show board
    ABC 
   +---+
  1|leg| 
  2| c |
  3| C |
  4|GEL| *
   +---+
  1. show lines
  Eb4-a3 : #65   (100.00%)
  Cb3xb2 : 0     ( 0.00%)
  Ga4-a3 : 0     ( 0.00%)
  Eb4-c3 : 0     ( 0.00%)
  Lc4-c3 : #-44  ( 0.00%)
  1. setup S/gel/-c-/-C-/GEL/
  1. show board
    ABC 
   +---+
  1|gel| 
  2| c |
  3| C |
  4|GEL| *
   +---+
  1. show lines
  Cb3xb2 : #51   (99.94%)
  Eb4-c3 : #65   ( 0.06%)
  Ga4-a3 : 0     ( 0.00%)
  Eb4-a3 : #-64  ( 0.00%)
  Lc4-c3 : #-52  ( 0.00%)
  
  It is a win if the elephant is in the middle. Notice that moving the elephant towards the enemy lion is winning in both positions and moving the lion forward is losing, but in the mirror-symmetric case, chick fight is also winning and elephant towards the other side is losing. At least in this case shogi is more drawish than western chess!
  In summary, it seems that trébuchets are quite rare (we did not find any), and most starting positions are draws with the occasional win for the starting player or loss for positions with an obvious weakness.
  
  
  ---
  
  