[Retros] Retractor 2.0

[andrew buchanan]

Hi Theodore & others.

There's a bunch of last-single-moves proof games from the 2009 Messigny composing tourney: 
https://pdb.dieschwalbe.de/search.jsp?expression=K%3D%27RIFACE%3A2009%27Composers focused on maximizing the number of "last single moves" determinable and were all Type C or (if Type A) had non-standard or obtrusive material.
So what is the shortest SPG to force at least one last move? For Type B, we saw 3 examples with 4.0 moves.

For Type A, the shortest I have now is quite clean, but surely speedier is possible: 
https://www.janko.at/Retros/d.php?ff=rnb1kbnr/ppp1pppp/8/8/8/q6P/1PPPPPPp/2BQKB2PG in 9.0. Last 2 single moves? C+ Jacobi & not yet Retractor
Type C one might expect to be doable much more quickly, but the shortest that I could find is: https://www.janko.at/Retros/d.php?ff=rnbqkQ1r/ppppp1pp/5n2/8/5p2/2P5/PP1PPPPP/RNB1KBNR
PG in 3.5. Last single move? C+ Jacobi & Retractor
I have a few suggestions for Retractor v2.0001:(1) The default max number of solutions should be infinite or big. 10 is way too small. Because of retro tries, I never saw the actual solution for the Type A problem above!(2) If you do truncate, you should put a warning on the output, to avert unwarranted joy.
(3) I would like to be able to try both WTM & BTM (i.e. Type A) without going back to the edit mode.(4) Tiniest of possible nits: for me "Retract White next" is disturbing. I personally would prefer "Retract White last".
Great work!

Thanks so much!Andrew
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://pairlist1.pair.net/pipermail/retros/attachments/20210416/e3a60274/attachment.htm>