Mark Thompson
 Math Education
 Math Recreations
 Abstract Games
 Great Thoughts
 Hip

Hip by Martin Gardner (around 1960)

Hip is published in Gardner’s New Mathematical Diversions, published by the Mathematical Association of America,  © 1995.  (This is a revised edition of New Mathematical Diversions from Scientific American, © 1966, which compiled Gardner’s “Mathematical Games” columns from 1959, 1960, and 1961.)  The two players alternately place stones of their color, trying to avoid placing them at the four vertices of any square.

Picture

For example, the Black player would lose if he places a stone at b6, by forming the square b6-a2-e1-f5.  The White player would lose if he places a stone at a1, by forming a1-d1-d4-a4.  Squares can be at any orientation, but they must be geometrically accurate squares -- equilateral and rectangular.  I’ve used Hip in my math classes to try to get across the idea of perpendicular slopes.

Double-Move Hip (my own variant):

As Gardner says, Hip on an even-order board is “strictly for squares.”  It is a solved game:  the second player can play the reflection of the first player’s moves and thereby assure himself of eventual victory.  To avoid this problem, I suggest a variant, Double-Move Hip, in which each move consists of placing two stones onto the board, except the first player’s first move.  In this way neither player has a clear advantage.  The same modification might save the game of Bridg-It.

Hip can be played using Jeff Mallett’s Zillions of Games program, which every abstract gamer should own.  I’ve also made the needed modifications to allow ZoG to play my two-move variants, which are easy.  I wrote Jeff Mallett about them; he may have incorporated the Double-Move Hip variant into the Zillions product by now.

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

[Math Education] [Math Recreations] [Abstract Games] [Great Thoughts]