The life and times of a Nine Men's Morris game playing AI


04-02-06 Morris is Victorious!

Friday's tournament proved to be a major challenge, but Morris, in typical fashion, took it in stride.  Other members of the Morris family were notably nervous, but unlike his emotionally crippled human progenitor, Morris seemed effortlessly able to keep his head in the heat of battle.  The early rounds of the tournament may have been the most nerve-racking when several opponents of dubious character refused the offer to play two games (taking turns moving first) in the hopes of stealing an undeserved victory via the outcome of a coin flip.  Fortunately, their prowess was as lacking as their probity.  Morris lost the coin flip twice during the tournament - the first opponent had a bug in his software that disqualified him and in the second such match, Morris was able to draw as black, forcing a second game in which he played a strong and aggressive win.

After advancing in the bracket, the quality of both play and sportsmanship rose dramatically.  In what was far and away the most spectacular NMM game this reporter has ever witnessed,  Morris faced off with a confident opponent, trained by the consummate competitor Shu Li.  In the first match, Morris played black, and neither opponent relinquished a piece during the opening.  The board was seemingly tied up without any visible grounds for advance.  Pieces were shifted around the board with all the spectators expecting a draw, but no repetitions were made.  In all the excitement, I didn't think to save the moves list, but at some point well into the middlegame, Morris was able to find an opening and formed a mill!  From that point on, he was in control, and managed to stage an upset victory from the weak side.  Bolstered by the confidence of the unlikely turnaround, Morris proceded to the final with a workmanlike white win.

The final round was played on the international stage when Morris matched up with Il Mulino, an entrant who drove all the way from Italy along the information super highway just to compete.  Biagio Miceli Jr. (Gino) sent over an athlete that was not going home empty handed.  After cruising to the finals, Gino's protege was clearly a force to be reckoned with.  Again, the opening was tight and until early in the middlegame, Morris' opponent would not relinquish the first move advantage.  Suddenly, there must have been a misstep, because despite a seemingly innocuous move by white, Morris' estimation of the board did a 180 and never looked back.

In a celebrity round match between the graduate and undergraduate champions, Andy Wolfe's clever creation managed to outmaneuver Morris in the opening, but eventually succumbed to Morris' 15-ply search in the middlegame.

Congratulations all around for an exciting bout of Nine Men's Morris.




Morris is ready for battle.  Test your mettle against a player who is poised to win in this Friday's tournament in NYC.  The newest version of the game provides an options panel that allows you to set weights that control how Morris values the various features of a board (ie. the importance of being up in pieces vs. having more move options).  You can save your weights to a file and load them back in, or load them into the newly available competition applet and compete your players against each other to see who wins.

Send me your best player!  I will be accepting submissions between now and Thursday @7:00pm.  On Thursday night, I will run a round-robin competition of all the player submissions including my own and one generated by the computer.  The prize for winning is dinner for two at your favorite restaurant (no, not dinner with me) and the honor of having your weights drive Morris' decisions in the tournament at Columbia.

For the serious competitor, see my notes on the weight values.

Feature Weight Followup: surprisingly, none of the submitted weights was able to consistently outperform the original basic weights that I had somewhat arbitrarily selected many weeks ago.  Fortunately, this didn't seem to matter much - when it came game time, Morris rose to the challenge.  Instead of awarding the grand prize to myself, I will be shipping prizes to all the entrants that I think you will enjoy.  Thanks so much for your interest and enthusiasm.  Morris' success is a tribute to us all.


With the tournament fast approaching, I'm gearing Morris up for competition.  In the meantime, get the game, learn to play, and hone your skills for the real challenge... Morris is scheduled for wide release early next week.

Known issues with the beta release:

  • Transposition Table Player does not free up memory after each game (workaround: close and open the program between games with TT Player to avoid running out of memory). 
  • Iterative Deepening Player and Transposition Table Player timing bug (causes poor play especially after undo)






  • Morris (release version)
  • Morris (debug version)