TacTix is a two-player game, where the players take turns removing counters from the board. The goal is to force the other player (the computer) to remove the last counter.
On any turn, you may remove counters from either a single row or a single column. The counters must be on adjacent squares (for example, you could not legally remove only two corner counters). You may remove as few as 1 or as many as 4 counters on your turn.
To make a move, use the mouse to select the counters you want to remove from the board, then press the Move button. Selecting a counter twice will cancel the selection.
The computer will make its move automatically after yours. To pass at the beginning of a game and have the computer make the first move, simply press the Move button without selecting any counters.

One more thing: it has been proven that the player who moves second can always win, if he or she plays perfectly. At the Expert level, the TacTix program will indeed play a perfect game. So if you want to win at the Expert level, you must let the computer move first !
Coutesy of Mazeworks