Big Tic Tac Toe

Tic-tac-toe is a paper-and-pencil game for two players, X and O, who take turns marking the spaces in a grid.

The player who succeeds in placing five respective marks in a horizontal, vertical, or diagonal row wins the game.

The main tactic for winning the game is to build the intersection ("forks"), which do not allow the enemy to block all possible ways of constructing fiver. In order not to lose, is necessary to timely interrupt the enemy's line of three or more pieces.