The game takes place on a grid of dots (of arbitrary size -- in this online version, the grid is eight dots by eight dots). Players take turns connecting one dot to an adjacent dot (diagonals are not allowed) by drawing a line between them. If a player's line completes a box, he scores a point and moves again. When all boxes on the grid have been scored, the game is over, and the player with the highest score wins.

In "Human vs. Human," you may play a game with another person sitting at the same computer. In "Human vs. Computer," you can play against a computer simulated opponent. In "Computer vs. Computer," you can watch two computer simulated players play against each other. The difficulty setting determines how competent the computer simulated players are at the game. On "Difficult," the computer simulated player(s) will play to the best of their ability. On lower difficulty levels, the computer may neglect to consider certain moves.

You can save your game by bookmarking the page in the game you want to come back to later. This may not always work; if you bookmark a page immediately after the computer makes a move, it might not make the same move when you return to the bookmark. To be safe, only save your game after a human player has made a move.

Cheating at this game is possible but discouraged as a general rule. However, on occasion it can be fun to play around with the game engine. The simplest way to cheat is to hit the "back" button on your browser when something happens that you don't like. You can also cheat by modifying the URL at a particular point in the game. Notice that the URL is comprised of name=value pairs, separated by ampersands. The letter(s) or number(s) before the equals sign is the name, and what comes after it is the value. If you modify some of the values you can change the state of the game. You can experiment if you like. Below are some specific things you can do.

Change the value of s1 and s2 to change the scores for player 1 and player 2, respectively.