Play Dots and Boxes Online for Free
Dots and Boxes turns a plain grid of dots into a battle of patience and counting. Every turn you draw one line between two neighbouring dots, and the moment you close the fourth wall of a square you claim it and immediately go again — so a single move can cascade into a whole row of captured boxes. The twist is that nobody wants to draw the third side of a box, so the real game is about who runs out of safe moves first. Play it on a 3×3 up to a 6×6 grid against three AI levels or a friend on the same device.
How to Play Dots and Boxes
The board is a square lattice of dots, sized from 3×3 to 6×6 boxes (the default, Auto, picks 4×4, 5×5, or 6×6 to fit your screen). A 4×4 board has 5×5 dots and 16 boxes to claim. Blue always moves first — and in solo play you choose whether you go first (Blue), second (Red), or at random. On each turn you draw exactly one horizontal or vertical line joining two adjacent dots, and each line segment can only be drawn once.
When the line you draw completes the fourth side of a box, you claim that box in your colour and must take another turn straight away. Because one line can sit between two boxes, a single move can complete two boxes at once — and as long as you keep closing boxes, you keep moving. If your line completes no box, play passes to your opponent.
The game ends when every possible line on the grid has been drawn. Whoever owns the most boxes wins. Ties are possible only on grids with an even box count: a 4×4 (16 boxes) or 6×6 (36 boxes) can finish drawn, while a 3×3 (9) or 5×5 (25) always produces a winner because an odd number of boxes can't split evenly. An undo button lets you take back your last move while you learn — against the AI it rewinds your move and the computer's whole reply.
Playing Against the Computer
All three levels use the same evaluation, which penalises any move that gifts a three-sided box, and think for a limited time on each move. Easy thinks briefly and picks at random among its four best lines, and Medium thinks longer and picks between its two best, so they can still hand you a chain — punish that and take it. Hard thinks longest and always plays the best line it finds. Easy and Medium are also greedy once a chain opens: they always run the whole chain you give them, so the double-cross works beautifully against them. Open nothing, force the computer to open a chain, then sacrifice two boxes to keep handing chains back and starve it of control. Hard can play the double-cross itself, declining the last boxes of a chain to keep control, so against it you also need the chain count on your side.
Frequently Asked Questions
If I complete a box, do I really get another turn?
Yes. Closing the fourth side of any box claims it and gives you an immediate extra move. You keep going as long as each line you draw completes at least one box, which is how players run off long chains of captured boxes in a single turn.
Can one line claim two boxes at the same time?
Yes. A line that sits between two boxes can close both at once if each only needed that one side. This double-box move is the engine behind the "double-cross" tactic, where you deliberately hand two boxes to your opponent to force them to open the next chain.
Why is it bad to draw the third side of a box?
Drawing the third side leaves the box with only one open wall, so your opponent can complete it on their next move — and then take another turn. Giving away the third side is how you lose control, which is why strong play means making only safe two-side-max moves until you're forced to give one up. Every AI level weighs against handing out these three-sided boxes, and Hard, which always plays the best line it finds, avoids them most reliably.
Can a game of dots and boxes end in a draw?
Only on grids with an even number of boxes. A 4×4 board (16 boxes) or a 6×6 board (36 boxes) can finish tied 8–8 or 18–18, but odd-count grids like 3×3 (9 boxes) and 5×5 (25 boxes) always produce a winner since the boxes can't split evenly.
Should I always grab every box in a chain the AI gives me?
Not against the Hard AI. Taking every box forces you to open the next chain yourself. The expert play is the double-cross: take all but the last two boxes of a chain, then sacrifice those two so your opponent has to open the following chain for you. It works especially well against Easy and Medium, which are greedy — they always run a whole chain you open for them, so keeping control with small sacrifices steers the game your way. Hard is not greedy: it can decline the last boxes of a chain itself to keep control.