Gridball Game

We played this game at school. It was popular in many places of the former USSR and was called something like football on squared paper. I called the computer version "gridball". Alternative names are welcome.



Computer doesn't think too far, in fact it counts only 2 moves ahead. So it's quite possible to win (if you know how to play, ha ha).

Latest updates:
04 Jul 2004   1.1 - mouse support was added.

Download Gridball 1.1


The rules are simple. The game begins at the center of the field where the "ball" is.

Each player "moves" the ball by drawing lines of three short segments either along the square side, or diagonally across the square.

The lines must not cross or touch any existing lines. Then the other player moves

and the game goes on.

If player A makes his move so that player B gets trapped, meaning he can't draw all his three lines,

then A hits a "penalty" move. A penalty is one straight line six squares long, vertical, horizontal or diagonal, no matter if across any lines or not.

If player B still can't move, the penalty continues. But there is a limit of 6 consequent penalties, so if the ball is still "in the mess", then player B begins his move with penalty.

There exist a number of versions of the rules. The program supports the simplest version described above.


  • On each your move try to limit your opponent's possible moves. If he is wrapped by your lines and forced to get out of it in only one way with his first line, then he has only two lines left for his actions. Thus you will always get more freedom than your opponent.
  • Field edges are important! When you get 3-4 squares close to edges, think thoroughly.
  • Before you make a trap for penalty, think ahead where does it stop. Right after it finishes your opponent may begin his series of penalties and sometimes even hit the goal. Sometimes you may prefer to leave a little exit for your opponent and force him retreat one or two squares and then make the penalty trap.
    Feedback       Source code (2004, BSD license)