Tap a line to begin
| Tap a line | Draw an edge between two dots. |
| Close a box | Claim it and take another turn. |
| New game | Clear the grid. |
Dots and Boxes is the game every schoolchild plays in the back of an exercise book. A grid of dots, and players take turns drawing one line between two neighbours. Complete the fourth side of a square and you claim it, write your initial inside, and take another turn immediately.
It looks like a game of chance and turns out to be startlingly deep. Mathematicians have written serious papers about it, because the endgame revolves around a counterintuitive idea: deliberately giving your opponent boxes in order to control who is forced to open the next long chain. Almost nobody discovers that on their own.
Avoid drawing the third side of any square. Once a box has three sides, your opponent simply takes it and gets another turn, which often starts a chain of free boxes. In the early game, only ever play edges that leave every nearby box with two sides or fewer.
The game is really decided by chains. Late on, the board becomes a set of connected runs of boxes, and whoever is forced to open the first one hands over the whole chain. Counting the chains before the endgame arrives tells you who is going to win.
Learn the double-cross sacrifice. When you are handed a chain, taking every box in it forces you to open the next one. Deliberately leaving the last two boxes uncaptured passes the turn back instead, and that single move wins more games than any other idea here.
Count parity when the board is still open. Whether the number of remaining chains is odd or even determines who gets forced to open first, and strong players steer the middle game toward the parity that suits them.
Yes, and you keep going as long as you keep completing boxes, which is what makes chains so powerful.
To avoid being forced to open the next, larger chain. Sacrificing two boxes to hand over the turn is the key advanced tactic.
Whoever has claimed the most boxes when every line has been drawn.
Very much so. It looks casual but the endgame has a well-studied mathematical theory behind it.
Nothing at all. The whole of Dots and Boxes is built into the page itself, which is why there is no loading bar and no waiting before you can play.