[Retros] Happy New Year

Andrew Buchanan andrew at anselan.com
Wed Sep 16 13:40:54 EDT 2015

Happy New Year, Noam,

Your harmonious identity 5775 = (78-1)*(78-3) encouraged me to think that a
symmetric diagram might be possible:
PG in 13.0 C+ Popeye 4.73 in 4.59 minutes.

For running on Linux, you can take the source of Euclide and maybe remove
the constraint that causes it to give up the first time it finds multiple
solutions for the same "strategy", and then compile for Linux. See

To all a request: I am looking to run a collection of 66 reasonably large
proof games in Euclide. Based on experimentation, I extrapolate that on my
laptop it would take about 1000 hours. Does anyone have any spare processing
capability that they are not using for bitcoin mining? Please let me know.


-----Original Message-----
From: Retros [mailto:retros-bounces at janko.at] On Behalf Of Noam Elkies
Sent: 14 September 2015 04:26
To: retros at janko.at
Subject: [Retros] Happy New Year

Not 3+ months early, but a different calendar:

White  Ra1 Sb1 Be3 Qe1 Kf1 Bg2 Sh1 Rd4 Pa2 Pb2 Pc2 Pd3 Pe4 Pf2 Pg3 Ph5 Black
Re5 Sa8 Bb7 Qc8 Kd8 Bd6 Sg8 Rh8 Pa4 Pb6 Pc7 Pd5 Pe6 Pf7 Pg7 Ph7

C+ Popeye 3.41 in ~1 second

The departing year 5775 on the Jewish calendar is not only palindromic but
blessed with numerous factors and thus many routes to an enumerative SPG.
I think this works:

White  Ra1 Sa4 Bc1 Qd1 Kg5 Bf1 Sh4 Rh1 Pa2 Pb2 Pc3 Pd2 Pe2 Pf3 Pg2 Ph2 Black
Rb8 Sd7 Bh3 Qd8 Ke8 Bh8 Sg8 Rc6 Pa7 Pb7 Pc7 Pd6 Pe5 Pf7 Pg6 Ph5

C+ Popeye 3.41 in ~1 second

A closer analogue to the 5776-solution problem would be

White  Rb4 Sc3 Ba3 Qf3 Kf2 Bf1 Sg1 Rh1 Pa4 Pb3 Pc2 Pd2 Pe2 Pf4 Pg2 Ph2 Black
Rb5 Sb8 Ba6 Qh6 Kf7 Bf8 Sf6 Rh8 Pa5 Pb6 Pc7 Pd7 Pe7 Pf5 Pg7 Ph7

but Popeye has been churning at it for 25+ hours now and has turned up only
924 solutions, so it might not finish before the relevant year draws to a
close (as it already has in Israel and Europe and points further East); I
suspect it's working so hard because it thinks that the Queens and Rb4/b5
have each wasted a move...  Perhaps a more recent Popeye, or a different
program, can check it in reasonable time.

Shanah Tovah,
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