Mark Thompson
 Math Education
 Math Recreations
 Abstract Games
 Great Thoughts
 TwixT
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TwixT by Alex Randolph (around 1960)

TwixT was published in 1962 by the 3M company as one of the earliest of their series of bookshelf games.  3M sold their game line to Avalon Hill which has since been acquired by Hasbro, and TwixT went out of print in the U.S. along the way.  But the game is still published in Europe where it  has many devotees, particularly in Germany.  You can frequently find used sets for sale on eBay, generally for under $10.  I got my set (not the one shown below, which I made!) from Funagain Games.  Believing as I do in the principle of “try before you buy,” I give the board diagram above on which you could play the game, by printing it out and using red and black pens to show moves.  The diagram is also marked for the notation used on the indispensible Richard’s PBeM server.

The players are Red and Black, and each player gets two opposite edges of a 24x24 board (with the four corners missing) as his goal areas.  In each turn a player places a peg of his color in any one of the vacant holes, except in his opponent’s goal areas, and may also place a link between any two of his pegs that are a knight’s move apart (at the opposite corners of a 2x3 rectangle), assuming such a link would not cross any existing link.  If he likes he can unlink two of his own pegs first.  The object is to form a bridge of your color between your goal areas.

I like this game because its tactics can be very tricky.  But although I have a 3M manufactured set, when playing it by e-mail I felt a need for a board that could be set on a shelf or carried around without the pieces falling out.  This I found in the form of a Lego base.  You can find one at Toys R Us in bright green or red, and they have pins exactly where TwixT holes should be (24x24 with the corners missing).

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Several coats of high-gloss model paint are needed to cover the garish plastic with a neutral white.  At American Science & Surplus (a chain of stores near Chicago and Milwaukee) I found large quantities of surplus plastic knobs in blue and red which would just fit snugly on the Lego base.  Then I cut bridges out of red and blue plastic detergent bottles with a sharp knife (at least it was sharp before I began), and tailored them with a woodburning tool.  Perhaps a soldering pencil would do.

I mark moves that have been completed (and the goal-rows) with single-height knobs, and I look ahead by placing double-height knobs where I expect myself and my opponent to move.  Knobs not yet in use mark the goal areas.  It’s not as nice looking as my 3M board, but it greatly improves my e-mail game.  (I’m still second-rate.)

By the way, the Mind Sports Olympiad website, in a section describing the game, now includes a detailed listing of a Twixt game I played against David Bush, with his annotations.  (I’m listed as N.N., because David had already posted the game before I could get him my permission to use my name.)  He is by far my superior, and I was honored that he chose our game to publish there.  It’s a good example of how handicapping can make for an interesting game between unequal opponents.  Twixt lends itself to an elegant handicapping system:  simply shorten the board along the weaker player’s direction.  In our game David gave me four rows, which in that instance were sufficient -- often they are not!

Diagonal Twixt, a variant (untested) by Mark Thompson

One strategic feature of Twixt which anyone who plays it seriously will soon discover is that the regions bound by lines of knight-moves proceeding out from the corners are effectively “owned” by the player whose edge is closest, because it is nearly hopeless for the opposing player to prevent a post there from linking to the near edge.  Contemplating this point, it occurred to me lately that “Diagonal Twixt” (played on the board shown below with the usual Twixt rules) might be a significant variant on the original game, possibly even an improvement.  The rationale is that the indisputable regions are a much smaller part of the board.  Only play-testing would tell whether the size shown here is really the best for playing Diagonal Twixt, but this size has the advantage that one could play it with standard Twixt equipment.  If you play Diagonal Twixt and have comments I’d be happy to hear from you!

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Questions, corrections, comments:  Send me e-mail at  markthom@flash.net

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