Four or Five in a Row
The rule stays simple: fill a whole line with your mark before the other player does. On a 4x4 board that line has four squares, on a 5x5 board five, and a single missed block can decide the game.
A Step Up From 3x3
Older children soon master the classic 3x3 game, which always ends in a draw with good play. Bigger boards keep the outcome open for longer and reward planning several moves ahead.
Framed or Hand-Drawn Style
The # style draws only the inner lines, thick and rounded at the ends, like a board drawn by hand. The framed style uses thin lines and closes the board with a thick border, which some players find easier to read on a 5x5.