Draw lines between dots to complete boxes and claim them. The player with the most boxes at the end wins! Challenge the AI or play with a friend.
⬛ Dots & Boxes
Draw lines to complete boxes. The player with the most boxes wins!
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Register Free 🚀About Dots & Boxes
Take turns drawing one line between two adjacent dots on a 4×4 grid of boxes. Complete the fourth side of a box and you claim it and go again. Most boxes wins. It is the classic exercise-book game, and underneath it is a genuine piece of mathematics.
Never draw the third side
This is the one rule beginners are missing. Drawing the third side of any box hands it to your opponent for free — and because claiming a box earns another turn, they will take it and then keep going through every other box you have left open.
The opening of the game is therefore about safe moves: lines that leave every box with at most two sides. When you run out of safe moves, the real game begins.
The chain is the whole game
Eventually the board fills up and every remaining move opens something. What is left is a set of chains — runs of boxes that all fall together once one is opened. Whoever is forced to open the first chain gives their opponent everything in it.
So the game is not about claiming boxes early. It is about controlling who runs out of safe moves first, which is decided long before any box is claimed.
The double-cross: giving boxes away to win
Here is the move that separates players who know the game from those who do not. When your opponent opens a chain of boxes for you, taking all of them means you must then open the next chain yourself — and hand them the bigger prize.
Instead, take all but the last two and then play a move that gives that pair back. You lose two boxes and your opponent is forced to open the next chain, which is usually much larger. Sacrificing two to gain eight is a standard winning technique, and it looks like a mistake to anyone who has not seen it.
Chain parity
There is a known rule for who should win. If the number of long chains that will form is odd, the first player is favoured; if even, the second. Skilled players spend the safe-move phase manoeuvring to change that count — deliberately joining or splitting future chains to flip the parity in their favour.
You do not need the theory to enjoy the game, but knowing that the endgame is decided during the boring-looking opening changes how you play it entirely.
Frequently asked questions
Do I get another turn after completing a box?
Yes, and you must move again. That bonus turn is what makes chains so powerful — one opened chain can be claimed end to end in a single visit to the board.
Why would I ever give my opponent boxes on purpose?
To avoid having to open the next chain. Giving back the last two boxes of a chain forces your opponent to open the following one, which is usually larger. Losing two to win eight is a standard technique.
Is there a way to guarantee a win?
Not in general, but chain parity gives a strong guide: an odd number of long chains favours the first player and an even number favours the second. Good play means steering the board toward the parity that helps you.
How big is the board?
A 4×4 grid of boxes, which is 5×5 dots and 40 lines to draw. It is large enough for several chains to form and small enough to finish in a few minutes.