No.1297 
Original Retro & PG problems 
No.1297 Sergey Shumeiko 
Solution: (click to show/hide) 
white Bf1c1 Ke1 Qd1 Ph2g2f2e2d2c2b2a2 Sg1b1 Rh1a1
black Bf8c8 Ke8 Qd8 Ph7g7f7e7d7c7b7a7 Sg8b8 Rh8a8
PG 7 (13+13) 

This should have been presented with unknown pieces and the stipulation “White is mated. PG in 7.0” with exactly the same solution.
C+ Jacobi in 1300s.
It looks even more suitable presented with PG 6.5 unknown pieces and #1. Indeed the position remains at home but the economy is reinforced with one more piece on the board. This is still C+ Jacobi:
stipulation PG 6.5
forsyth X1XXX1XX/XXXXXX1X/8/8/8/8/XXXXXXX1/XX1XXXXX ColorThePieces
stipulation #1
1.h4 Sc6 2.h5 Sd4 3.h6 Sxe2 4.hxg7 Sxc1 5.gxf8=B Sd3+ 6.Ke2 Se1 7.Bxe7 Qxe7#
Option PG 7.5:
2XXXXXX/X1XXXXXX/8/8/8/8/XXXXXXXX/1XXXXX1X
ColorThePieces stipulation #1
1.a4 Sc6 2.a5 Sd4 3.a6 Sxe2 4.ab Sxg1 5.bcS Sf3+ 6.Ke2 Se1 7.Sxe7 Rc8 8.Ra2 & Qxe7#
Phoenix (wS). Ceriani. Excelsior.
Сергей Шумейко
X1XXXX1X/XXXXXXX1/8/8/8/8/XXXXXX1X/XXXXXX1X
PG 6.5 & #1
1.g4 Sc6 2.g5 Sd4 3.g6 Sxe2 4.gh Sxg1 5.hgS Sf3+ 6.Ke2 Se1 7.Sxe7 & Qxe7#
Phoenix (wS). Ceriani. Excelsior.
Yes, this variation is even more homogeneous with involved Knights from both sides.
From Sergei I got 2 FENs – with normal and unknown pieces. Finally used the one with pieces as otherwise couldn’t animate the solution. Maybe it would be better to leave it without animation then..
Ещё одна симпатичная картина, с забавной игрой коней:
Сергей Шумейко
P1PPPP1P/PPPPPPPP/8/8/8/8/PPPPPPPP/P1PPPP1P
PG 6.0 ColorThePieces stipulation & #1
1.Sc3 Sc6 2.Sd5 Sd4 3.Sxe7 Sxe2 4.Sxg8 Sxg1 5.Sf6+ Ke7 6.Se8 Se2 & Qxe2# 🙂
The “visible” problem, dear Julia, is too light, but becomes interesting with unknown pieces. Among the 3 variations Sergey proposed, my favorite is the last one in 6.0 with harmonious holes on the 4 Knight squares. But of course this is to the author to decide.
Мне последняя версия PG 6.0 тоже нравится больше. Красивая диаграммная картинка. Задание можно придумать с юмором: PG 6.0 & #1. Where are the horses? 🙂
Есть другие варианты?
Если Юлия согласится поставить задачу под No.1297.1 со скрытыми фигурами X1XXXX1X/XXXXXXXX/8/8/8/8/XXXXXXXX/X1XXXX1X, буду доволен.
P.S. Sorry, I don’t speak English.
Popeye Windows32Bit v4.59 (1024 MB)
1.Sb1c3 Sb8c6 2.Sc3d5 Sc6d4 3.Sd5*e7 Sd4*e2 4.Se7*g8 Se2*g1 5.Sg8f6 + Ke8e7 6.Sf6e8 Sg1e2 dia
r1bqNb1r/ppppkppp/8/8/8/8/PPPPnPPP/R1BQKB1R
& 7.Qd1xe2#
solution finished. Time = 0.560 s
BeginProblem
Stipulation dia6.0
Option Variation NoBoard SetPlay Defence 1
Pieces
white Bf1c1 Ke1 Qd1 Ph2g2f2d2c2b2a2 Se8 Rh1a1
black Bf8c8 Ke7 Qd8 Ph7g7f7d7c7b7a7 Se2 Rh8a8
EndProblem
The last version is cooked:
1.Sc3 e5 2.Sf3 Sa6 3.Sd5 Sb8 4.Sxe5 Sa6 5.Sxc7+ Sxc7 6.Sxf7 Se7 7.Sd6#
Thanks. The task in the basket.
X1XXXX1X/XXXXkXXX/8/8/8/8/XXXXXXXX/X1XXXX1X
PG 6.0 & #1. Where are the horses?
One way to get an animated solution *and* undefined pieces is to end with a dummy move that turns the last position into what we want. For example, here’s the p2wsolution for a PG 6.5 and #1, which I think was the intention:
1.h2h4 Sb8c6 2.h4h5 Sc6d4 3.h5h6 Sd4*e2 4.h6*g7 Se2*c1 5.g7*f8=B Sc1d3 + 6.Ke1e2 Sd3e1 7.Bf8*e7 Qd8*e7 + 8.Ra1a1 [+nOa1][+nOb1][+nOd1][+nOe1][+nOf1][+nOg1][+nOh1] [+nOa2][+nOb2][+nOc2][+nOd2][+nOe2][+nOf2][+nOg2]
[+nOa7][+nOb7][+nOc7][+nOd7][+nOe7][+nOf7][+nOh7] [+nOa8][+nOc8][+nOd8][+nOe8][+nOg8][+nOh8]
The drawback is that the dummy move will appear as part of the solution. To get something perfect we would need to make a feature request to Dmitri Turevski.