Original Fairy problems
JF-R2021-22:
01.01.2021 - 31.12.2022
No. 1648 S. K. Balasubramanian &
Velmurugan Nallusamy
India
original - 12.09.2021
white Bf1c1 Ke1 Qd1 Ph2g2f2e2d2c2b2a2 Sg1b1 Rh1a1
black Bf8c8 Ke8 Qd8 Ph7g7f7e7d7c7b7a7 Sg8b8 Rh8a8
PG 13,5 16+16
PWC
PWC
Solution: (click to show/hide)
The text on the main page is wrong (PG 3.5), should be PG 13.5. 5th white move is also wrong (rook is reborn on h8, not knight).
I have serious doubts that this is correct due to the many free moves the white queen has, but cooking will take too much time.
Thank you, Joost! My mistake about the 5th move. Have wrongly added [h8=S] to the first half move, but there’s a wS on the second half move. Complicated animation for the reborn and promotion. The only way for it to work I’ve found is writing solution as “5.Qh8*g7[+bRh8] Rh8*h7[+wPh8] [h8=S] “. But the program changes +wPh8 to +Sh8 right away 🙁
The authors reported it is C+ by Popeye. I tried to test but it took too long, haven’t got any result for a day.
Sorry, it was a mistake about “C+ by Popeye”.
The comment by S. K. Balasubramanian about testing:
“I tested only for first 8 moves & the testing was done by Jacobi. It was sound. I further tested for a=>b for the following values of a & b:
a=1, b=8.
a=2, b=9,
a=3, b=10,
a=4, b=11,
a=5, b=12,
a=6, b=13.”
Partial testing for at-home positions is not very useful IMO. Almost any piece could’ve moved away and back, so all you tested is that your intention is unique.
Nice idea, but Joost is right.
With this kind of condition and many moves, a lot of things can happen.
Here is a cook :
1.d4 Sc6 2.c4 Sxd4(c6) 3.h4 bxc6(b7) 4.bxa8=Q(Rb7) Rxb2(b7) 5.b8=S Rxb8(Sb2) 6.h5 Sb5 7.cxb5(Sc4) Rxb5(Bb8) 8.h6 Rxb8(Bb5) 9.Qxb8(Ra8) Sxh6(Rg8) 10.Qb7 Sxg8(Rh6) 11.Qxc6(b7) Se5 12.R6h4 Sxc6(Qe5) 13.Qg3 Sb8 14.Bd3
Thanks for finding the cook sir. We tried with Jacobi but couldnt complete the testing even after a day. Any suggestion on how to test these types of problems. We wanted to have Queen tempo move in addition which seems to have created issue. We rectified the issue but again we couldnt test it. Your suggestions will be much helpful !!
With existing tools, there is no way to fully test these types of problems.
The best tool to find cooks is PG demolition mode of Jacobi.
It didn’t find a cook in your problem (maybe it could if running a very long time), but studying the strategy tried by Jacobi I could build the cook after some efforts. A kind of comptuter+human association.