How to Play Dots and Boxes: Rules, Chains and Winning Strategy

Dots and Boxes looks like a child's game, and the rules take a minute to learn. Underneath, it is one of the deepest pencil-and-paper games for two players. Beginners play by instinct. Experienced players count chains and decide who will be forced to open them. This guide gives the rules, the one habit that stops you giving boxes away, and the strategy that wins close games.

What you need

• Paper and a pen or pencil, or a screen with a game.
• A grid of dots. A good first size is 5 by 5 dots, which makes a 4 by 4 grid of 16 boxes. A 3 by 3 dot grid (4 boxes) is too small to be interesting.
• Two players.

Rules

1. Players take turns. On your turn you draw one line between two dots that are next to each other, horizontally or vertically. No diagonals.
2. If your line completes the fourth side of a box, you write your initial in the box and take another turn.
3. If your line did not complete a box, your turn ends.
4. The game ends when every line is drawn. The player with more boxes wins.

The extra-turn rule is what makes the game interesting. Completing a box is a reward, but it also forces you to move again, and that can be a problem.

The golden rule: do not draw the third side

If you draw the third side of a box, your opponent can finish it, take the box and move again. So avoid giving the third side of any box for as long as you can.

In the opening, nobody has to. There are plenty of lines that make no box close to completion. Play them. The real game starts when those safe lines run out.

Chains and loops

As the board fills up, it divides into groups of boxes joined in a row or a ring.

• A chain is a row of boxes, each open to the next. Chains can be short (one or two boxes) or long (three or more).
• A loop is a ring of boxes joined end to end.

When someone is forced to draw a line inside a chain, their opponent can complete boxes all the way along it. That is why the end of the game is about who has to open the first long chain.

The endgame: all-but-two and double-dealing

Imagine all the safe lines are gone and you have to open a chain for your opponent.

• Your opponent can take all the boxes in the chain. But then they must move again, and may have to open the next chain for you.
• A smarter opponent takes all the boxes except the last two and then draws the line that hands you those two boxes in one go (a move called a double-deal or hard-hearted handout). You take two boxes, but you now have to move next, and you must open the next chain.

So there is a trade: give up two boxes to keep control, meaning your opponent is the one forced to keep opening chains. In a position with several long chains, control is usually worth far more than two boxes.

When to keep control, and when to take everything

• Take everything if it is the last chain, or if taking all the boxes wins you the game.
• Double-deal if there are more long chains still to come, and the boxes you give away are fewer than the boxes you will win next.
• Count the rest. Before you decide, add up the boxes in the remaining chains.

Opening chains in the right order

When you are the one who has to open chains:

1. Open the shortest chain first (it costs the least).
2. Remember that a loop costs the player in control four boxes to decline, not two, so loops are worth opening when you are trying to make keeping control expensive.
3. Always count the boxes in every remaining chain before you choose which one to open.

Practical tips

1. Count safe moves. In the middlegame, count how many lines can still be drawn without giving a third side. The player who runs out first has to open a chain. Try to change the parity of that count by making or avoiding a move that cuts one chain into two.
2. Sacrifice early to change the structure. Sometimes giving away one or two boxes early forces the board into the shape you want.
3. Do not grab boxes automatically. Every time a box is offered, ask whether taking it hands the move back to you at a bad time.
4. Think about the number of long chains. More long chains generally favour the player who has control. A board that breaks into one big chain favours the player who is not forced to open it.
5. Start with bigger boards when you are learning. Larger boards have more room for chains and more tactical depth.

Variations

• Different board sizes. Rectangular grids such as 5 by 7 dots are common.
• Pre-filled lines. Draw a few lines before the game to change the structure.
• Scoring by area. Give some boxes more points, for example boxes that are marked with a star.
• Three or four players. Works, but the strategy is mostly about not being the one who opens a chain.

Play online

Free Dots and Boxes games run in your browser. Several are in our catalog: Dots and Boxes, Dots and Boxes 2 Player and Dots and Boxes Deluxe. Check each page for the board sizes and modes it offers. More paper games are covered in how to play Battleship, how to play hangman and the best board games for 2 players.