Chain Reaction is played on an 8 by 8 board. Players take turns to move.
On each move, the player  may  select an empty  square, or one they already
own. Squares  belonging  to other  players may not be chosen. If the square
was unowned, it becomes the property of the player, and is given a value of
1. If the square was owned by the player, the value is incremented.

   If  the  value of a square  ever  exceeds  the maximum permitted of that
square, it explodes. Squares  in  the  corner  have a maximum of 1, squares
touching an edge, but not on a  corner  have a maximum of 2, and squares in 
the interior have a maximum of 3.

   When a square explodes, it becomes unowned, and it's value  is  reset to
0. The 4 squares  touching  it become  owned by the owner of the  exploding 
square, and  their  values are incremented. If any of these are above their
maximum, they explode, giving rise to the chain reaction.

   If, at the  end  of a move, any of the players have no squares, they are
dead, and get no  more  turns. When there is only one person left, they are
the winner.