Although very unlikely, the starting position could be a forced win for Black. This would mean it is a position of mutual zugzwang, in the strong sense that whoever moves first loses. Wikipedia refers to one such position as trébuchet. Such positions are rare, and it would be a big surprise if the starting position was one of them.

The starting position has another property in that it is symmetric. White and Black have exactly the same possible moves (when written in descriptive notation). Are there any symmetric positions that are known to be a mutual zugzwang?

  • 1
    Great question, thank you! Nit: I think the trebuchet is a specific example of full point Zugzwang (KPvKP) rather than a synonym for full point Zugzwang.
    – Laska
    Oct 11, 2017 at 15:28
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    The trebuchet is symmetrical if you are playing on a 7x8 board! :D
    – Laska
    Oct 11, 2017 at 15:29
  • 1
    @Laska I think maybe the wiki article has been updated and expanded since I asked this question. Oct 11, 2017 at 19:49

2 Answers 2


You can easily construct many such positions. For instance:

4k3/8/3P1P/8/8/3p1p2/8/4K3 w - - 0 1

First to move loses - either by moving a king and allowing the opponent to promote or by losing one (and subsequently next) pawn.

  • What about: Kd1 f2 Ke1 f1=Q Kxf1 d2 Ke1........
    – AAM111
    Dec 2, 2016 at 0:05
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    @OldBunny2800: Your king uses an invisibility cloak at Ke1 so the pawn at f2 can't see it?
    – user21820
    Dec 2, 2016 at 1:33
  • @user21820 ????
    – AAM111
    Dec 2, 2016 at 1:43
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    @OldBunny2800: Your suggestion in your comment is invalid because you moved the king into check.
    – user21820
    Dec 2, 2016 at 2:14
  • 1
    @user21820 ohhhh, my bad.
    – AAM111
    Dec 2, 2016 at 3:04

In all the chess books I've read, "trébuchet" is actually one particular case of a full-point double-zugzwang: the most minimalist one you can get, with only one pawn for each player:

8/8/8/3pK3/2kP4/8/8/8 w - - 0 1

This pattern can be translated to 30 different positions, with the black pawn on any square in the b7-g7-g3-b3 rectangle. Whoever is on move will lose.

  • That's a cool position, unfortunately it doesn't have mirror symmetry
    – klm123
    May 4, 2021 at 10:49
  • 1
    @klm123 No mirror symetry, but a point symmetry.
    – Evargalo
    May 6, 2021 at 8:21

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