How to play Dots and Boxes

Dots and Boxes is a classic pencil-and-paper game that has entertained players for well over a century. Here you play it in your browser against a computer opponent — no download, no sign-up, just a clean grid and a sharp little bot. The board starts as a simple array of dots. By default it is a five-by-five field of boxes, which means a six-by-six lattice of dots, but you can switch to a smaller three-by-three or a larger seven-by-seven board for a longer game.

The goal

You and the bot take turns drawing a single line — one short horizontal or vertical edge — between two dots that sit next to each other. Whenever a line you draw completes the fourth side of a one-by-one box, you claim that box in your colour. The aim is simple: own more boxes than your opponent by the time every edge on the grid has been drawn. If you each end up with the same number of boxes, the game is a draw.

How to play

• Tap or click any empty edge — the gap between two neighbouring dots — to draw your line there.
• The bot replies with its own line a moment later.
• Whenever a line completes a box, the box fills with the owner's colour and is marked with their initial.
• Completing a box earns you an extra turn — keep drawing while you keep closing boxes.
• The running score for you and the bot sits in the header at all times.

The all-important extra turn

The single rule that gives Dots and Boxes its depth is that completing a box lets you move again — and you keep moving as long as you keep completing boxes. A well-placed run can let you sweep a whole chain of boxes in one turn. That is why the game is far more than randomly filling in lines: every move either builds toward your own boxes or quietly hands chances to your opponent.

Strategy

The heart of good play is avoiding the third side. The moment a box has three of its four sides drawn, your opponent can complete it for free on their next turn — so try not to be the one who draws that third edge. Early on, fill in "safe" edges that leave every box with no more than two sides. As the board tightens and safe moves run out, the player forced to open a region first usually loses it. Strong players think in terms of long chains of boxes and use a tactic called the double-cross: instead of greedily taking every last box in a chain, you sometimes leave the final two for your opponent, forcing them to open the next chain for you. The bot here always grabs a free box when one is available and always prefers a safe edge over handing you a gift, so beat it by steering the board toward chains that fall your way. Press the new-game button or the N key at any time to start a fresh board, and use the board-size control to make the game shorter or longer.