Fairy chess composition
 No.1326 Stephen Emmerson (U.K.) Original Retro & PG problems JF – R2017-18

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 No.1326 Stephen Emmerson U.K. original – 18.09.2018 Solutions: (click to show/hide) white Bf1c1 Ke1 Qd1 Ph2g2f2e2d2c2b2a2 Sg1b1 Rh1a1 black Bf8c8 Ke8 Qd8 Ph7g7f7e7d7c7b7a7 Sg8b8 Rh8a8 PG 4.5         b) Bf3→h6        (16+16) Horizontal Symmetry Circe a) 1.Sb1-c3 d7-d5 2.Sc3-e4 d5*e4[+wSe5] 3.Se5-c4 Bc8-g4 4.Sc4-a3 Bg4-f3 5.Sa3-b1 {dia} b) bBf3-->h6 1.Sg1-f3 d7-d6 2.Sf3-e5 d6*e5[+wSe4] 3.Se4-g5 Bc8-h3 4.Sg5*h3[+bBh6] e5-e4 5.Sh3-g1 {dia (C? Popeye)} Rundlaufen with different wSs. White homebase after odd number of moves. No repeated moves (Pawn one-two). Tested with a tweaked version of Popeye. (Author)

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François Labelle
September 19, 2018 00:51

I think that the condition should be called “Horizontal Symmetry Circe” since it is a variant of “Symmetry Circe”. It is not the horizontal counterpart of “Vertical Mirror Circe” which takes as its starting point the normal rebirth square, and not the capture square as in this problem.

In any case, the condition is equivalent to the combination “Circe Symmetry VerticalMirror” and can be tested as such in Popeye and Jacobi — no tweaking necessary. (For those curious, “Symmetry” overrides the normal rebirth square, and that square is further transformed by “VerticalMirror”.)

Stephen Emmerson
September 19, 2018 01:44

I wasn’t aware of a condition called “Vertical Mirror Circe” is this the same as is produced by specifying “Circe VerticalMirror” in Popeye? Are there problems using it?
Also I hadn’t realised one could modify SymmetryCirce with VerticalMirror in Popeye – an unfortunate way to specify a horizontal mirror; and I can’t figure out a way to specify what would be a vertical mirror equivalent (e.g. x on a3, rebirth on h3).
I thought of Horizontal Symmetry Circe but my thought was that, given a variant called “Vertical Symmetry Circe” too, it would not be obvious which was which from the name alone. Though “Symmetry Circe” says nothing at all about which symmetry, so I guess it’s no worse.

François Labelle
September 19, 2018 05:50

For an example problem using “Vertical Mirror Circe”, see https://juliasfairies.com/problems/jf-2013-i/no-273/ .

To specify Vertical Symmetry Circe, the best attempt is “Circe Symmetry Diametral VerticalMirror”. It works in Jacobi, but fails in Popeye (“nonsense combination”).

If the meaning of horizontal symmetry is not obvious, then people can use Google. It’s a math concept.

By the way, WinChloe calls your condition “Circé symétrique horizontal”, with 3 problems in its database.

dupont
September 19, 2018 19:58

Btw the diagram position is false, as it shows the initial game array.

Joost
October 15, 2018 23:33

Would Pe4->e5 with 2 solutions work?

Joost
October 15, 2018 23:36