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The Game of Jam

Jam is a game invented by John A. Michon [1]. It has nothing to do with the misnamed Traffic Jam puzzle.

You play against your computer. The board depicts a network of 9 roads and 8 cities. Players take turns selecting a road. The goal of the game is to take all the roads that pass through a city.

If the box "I move first" is checked, you have to click the "Start" button which will cause the computer to make the first move. Computer selections appear in red, yours in blue.

<hr> <h3> This applet requires Sun's Java VM 2 which your browser may perceive as a popup. Which it is not. If you want to see the applet work, visit Sun's website at, download and install Java VM and enjoy the applet. </h3> <hr>

Jam has a secret known to the computer and waiting to be discovered by you. It's pretty hard to beat anybody in the know. Computer, being one of the few privileged, makes, from time to time, benevolent mistakes. See if you can beat it.


  1. E.R.Berlekamp, J.H.Conway, R.K.Guy, Winning Ways for Your Mathematical Plays, v2, Academic Press, 1982.
  2. M. Gardner, Aha! Insight, Scientific American / W.H.Freeman and Company, 1978

Copyright © 1996-2008 Alexander Bogomolny

























The secret

The secret is very simple. It's explained in the diagram. As the games of Fif and Fish Soup, Jam is TicTacToe in disguise. Roads correspond to the squares of a 3×3 board. There are nine of them. In TicTacToe the goal is to occupy 3 contiguous locations either horizontally, or vertically, or diagonally. There are 8 possibilities in all. These correspond to the cities in Jam.


  1. E.R.Berlekamp, J.H.Conway, R.K.Guy, Winning Ways for Your Mathematical Plays, v2,

Copyright © 1996-2008 Alexander Bogomolny