The Computer Olympiad

This is my text as it was published some time ago on the Challenges-page of the 7th Computer Olympiad 2002 in Maastrich (link to the rules is no longer functional):

TwixT is a two-player abstract board game, invented by Alex Randolph. A short introduction to the rules can be found here: As for Go, it is hard to write a program for TwixT although the rules are quite simple. The number of possible moves is large and judging a board position is fairly difficult. Currently no program for TwixT exists, at least not to my knowledge.
This is a call to write TwixT-programs for the Computer Olympiad 2003, I plan to finish my own TwixT-program by then

In the meantime several Computer Olympiads took place, without any attending Twixt-program. So hopefully, there will be a Twixt-contest at one of the next Computer Olympiads. See you there!

Current Twixt-playing programs

A list of current programs can be found on a separate page.


Remarks on rules we should agree on for new Twixt-programs:

  • The convention for coordinates: The rows are numbered 1 to 24, and the columns are lettered A to X.
  • The player playing top-bottom makes the first move.
  • We should use the pie-rule. (Explanation by David Bush: „After the first player (Red) makes the first move, the 2nd player has the option of responding normally as Black, or swapping sides. If sides are swapped, the player who moved first as Red is now Black, and makes the next move. Sides may be swapped only once per game. If the 2nd player chooses not to swap after Red’s first move, then sides may not be swapped at all that game.“)
  • For the normal move, ‚automatic linking‘ is used: Any links which can be added to this peg, without removing other links, are automatically added.
  • It has to be discussed if ‚Unlinking‘ and ’non-automatic linking‘ has to be implemented for the first Twixt-programs.


Currently two systems for notation of moves exist, the one used in Germany and the one used in North America. They differ in the syntax for ‚Unlinking‘ and ’non-automatic linking‘.

  • American notation: The notation for moves is described (and used) in An asterisk „*“ can be used for „automatic“ links, but this is optional.
  • German notation: Dashes „-“ are added after the coordinates, one for each „auto link“ played. If a link is removed, this is written down in brackets (e.g. (U8-T10) means that the link between the pegs U8 and T10 is removed). There is no syntax for ’non-automatic linking‘ known to me.