3-A-Side is a simple tactical board game which was published by Spears Games in the 1980s. It formed part of a series of several such small games, quite possibly all by the same (uncredited) designer. Other titles in the series included “Energizer” and “Ins & Outs”—all of them involved in some way the game mechanic of determining how many spaces a piece could move by counting the number of other pieces (sometimes including one's opponent's) in particular spaces.

The game is deterministic and symmetric and so a strategy-stealing argument shows that it is either a win for the first player or a draw by infinite play—however I will give a slight modification to the rules to fix this. With this change I do not know who wins with perfect play, or indeed whether this problem is within reach of computation.

How to play 3-A-Side

You need:

  • A total of 7 counters in three distinguishable colours, consisting of three “men” for each of the two players, and one “ball”.
  • An isometric hexagonal board of side length four, modified as shown:
         |   |   |   |
        / \ / \ / \ / \  
      / \ / \ / \ / \ / \  
    | \ / \ / \ / \ / \ / |
    |  x---x---0---x---x  |
    | / \ / \ / \ / \ / \ |
      \ / \ / \ / \ / \ /
        \ / \ / \ / \ / 
         |	 |   |	 |
    Note that two opposite corner vertices have been removed, and instead there is in each case a direct connection between the two edge vertices next to the removed corner, so it is possible to move between these vertices in a single step. Each GOAL is adjacent to the four vertices on the corresponding edge.

    @ and 0 denote the start positions of the pieces. If you're intelligent enough to remember where the pieces start then they need not be marked on the board.

To play:

  • Set up the board by placing each player's three men on three adjacent @s, and the ball on the 0 marked in the diagram above.
  • Each player in turn takes two moves. (Variant suggestion by me: the first player takes one move, then on each subsequent turn each player has two moves. This would seem to offset the advantage in starting; at the very least it destroys the trivial game-theoretic argument which shows that the second player cannot win against correct play.)
  • On each move you may either:
    1. Move one of your men a single step to an adjacent vertex (i.e. to the next vertex in any of the six directions parallel to the sides of the hexagon; or between the two leftmost or the two rightmost vertices as the board is shown above, along the extra adjacency denoted by the parenthesis); or
    2. Move the ball. In a single move you may move the ball any number of steps up to the number of your men adjacent to the ball at the start of the move.
  • No piece may be moved onto or through a vertex occupied by another piece, and only the ball may be moved into a goal. If the ball enters a goal then the player defending that goal (the one whose men started nearer it) loses the game.
It is suggested that you may like to play for the best of five or some other number of goals (compare foosball.)