Dots and boxes online: close boxes and score points

In dots and boxes two players take turns joining dots with lines; whoever draws the fourth side of a box keeps it and moves again. Here you can play dots and boxes against the computer or with two players on one device.

Source: Wikipedia: Dots and boxes – Regeln, Strategie (Ketten, Doppelzug). Updated: 30 September 2026.

How it is calculated

Dots and boxes: the rules

The board is a grid of dots. Players take turns joining two neighbouring dots with a line.
Whoever draws the fourth side of a box closes it, scores a point and must move again. One line can even close two boxes at once.
The game ends when all lines are drawn. The player with more boxes wins.

How to use the game

Pick the board (3×3, 4×4 or 5×5 boxes) and the opponent: three computer levels or “Two players” on the same device. Tap or click a line. Your lines and boxes are blue (○), your opponent’s orange (×). “Undo move” takes back your last move together with the replies. On a keyboard, pick the line with the arrow keys and place it with Enter.

Strategy

At the start one simple rule applies: do not draw the third side of a box, because that hands it to your opponent. When no safe lines are left, the boxes form chains in which every line gives the whole chain away. Beginners take everything and then open the smallest chain. Experienced players use the double-cross: they take all boxes of a chain except the last two, hand those over and force the opponent to open the next chain. Keeping control usually wins the long chains.

The computer

Easy mostly plays at random. Medium takes every box, never gives away a third side and only then opens the smallest chain. Hard plays like Medium but calculates every sequence of moves exactly in the endgame (from about 16 open lines), including the double-cross. That makes Hard especially strong at the end. When you beat the computer you can share the result as a challenge. More board games: tic-tac-toe, connect four, checkers and battleship.

Frequently asked questions

How do you play dots and boxes?

Players take turns joining two neighbouring dots. Whoever draws the fourth side of a box keeps it and moves again. At the end the player with the most boxes wins.

Who starts, and how big is the board?

You can choose: you or the computer starts. The boards are 3×3, 4×4 and 5×5 boxes; 2×2 is good for learning, and 5×5 is considered a board for experts.

What is a double-cross?

On a long chain you take all boxes except the last two. You hand those over with one line, the opponent has to take them and then open the next chain. That way you keep control.

Can two people play on one device?

Yes. Choose “Two players” as the opponent and both take turns on the same screen.

How strong is the computer?

On “Hard” it calculates every possibility in the endgame and uses the double-cross. Early on it plays like an attentive player who never gives away a third side.

Sources and legal basis

As of: 30 September 2026 · Editorial policy