[Retros] Retractor 2.0 now available online
hwatheod at cs.stanford.edu
Sat Apr 10 16:23:26 EDT 2021
Make sure you use http:// and not https:// (and make sure you don't have a
browser setting that automatically changes http to https).
On Sat, 10 Apr 2021, Alexander George wrote:
> Hi. I keep getting the message:
> The requested URL /~hwatheod/retractor2/retractor.html was not found on this server.
> On Sat, Apr 10, 2021 at 1:56 AM Theodore Hwa <hwatheod at cs.stanford.edu> wrote:
> Hello retro enthusiasts,
> Retractor 2.0 is now available online as an application in your browser at
> For those not familiar, Retractor is a program for exploring retro
> problems. It lets you setup a position and play backwards from it, and
> warns you if it detects an illegal position. It reports the number of
> captures and promotions in a position. It can also solve some "Last N
> moves" problems.
> For those of you who have been around this list for a while, Retractor 2.0
> is the successor of Retractor 1.0 which was a Windows application
> developed by myself and Chad Whipkey in 1998.
> Right now, Retractor 2.0 is pretty much a straight port of Retractor 1.0
> immediate items for improvement are (1) taking promotions into account
> when counting pawn captures, and (2) a more general method for detection
> of illegal retro-cages (right now, some common cases are hard-coded).
> I am using the "Last Single Move" problems (types A-D) at
> https://www.janko.at/Retros/Records/LastMove/index.htm as benchmarks for
> improving Retractor. When going through those problems, I found that when
> Retractor cannot solve one of them, it's usually because of (1) and/or
> If you are interested in the source code, it is available on github at:
> Any and all feedback, comments, contributions for Retractor are
> appreciated! You can contact me at this email address, or on the github
> page above.
> Ted Hwa
> Retros mailing list
> Retros at janko.at
> Alexander George
> Department of Philosophy
> Amherst College
> Amherst, MA 01002
More information about the Retros