Dots & Boxes
Draw lines, complete squares, and out-box the computer.
How to play Dots & Boxes
On your turn, click near an empty edge between two dots to draw it. Completing the fourth side of a box claims it for you and grants another turn. When every edge is drawn, whoever owns more boxes wins. The trick is to avoid handing your opponent a chain of free boxes.
The player who grabs every box loses
Dots and Boxes looks like a race to claim squares, and that is the trap. Games between players who know the trick are decided by who is forced to open the last long chain, not by who snatched the early boxes. On your turn you draw one edge between two dots; completing the fourth side of a box claims it and grants another move. So the whole early game is about never drawing the third side of a box, because a third side is a gift: it lets the opponent add the fourth, take the square, and keep taking down the whole chain.
The opening is therefore a countdown of safe moves. Both sides fill in harmless edges until the safe ones run out and somebody must crack a chain open. Everything before that moment is jockeying to make sure the somebody is not you, or that the concession is as small as possible when it is.
The double-cross, with numbers
Here is the endgame move that wins, and it feels wrong the first ten times. Say the computer is forced to open a chain of six boxes to you. Greed takes all six; greed loses. Take four, and when two boxes remain as a joined pair, do not take them. Draw the edge that closes them off as a little domino for the computer instead. It must accept those two boxes, and then it is on move again with the safe edges long gone, forced to open the next chain for you. You spent two boxes to keep control; the computer got two and paid with the next chain of six or eight. Repeat the sacrifice at the end of every chain except the last, which you swallow whole. This all-but-two move is the double-cross, and against an opponent who does not know it, close games turn into blowouts.
Loops, chains that close into a ring, run the same logic at a higher price: declining a loop means leaving the last four boxes as two pairs, not two. Loops are expensive currency, which is why part of the craft is steering the board toward chains when you expect to hold control and toward loops when you do not.
Counting chains before they exist
Strong players think about parity long before the endgame arrives. The chain rule says control of the endgame follows the number of long chains, meaning chains of three boxes or more, and that number can be steered. Count the dots: with an even dot count the first player wants an odd number of long chains, and the second player wants it even; an odd dot count reverses the wants. You will not always get your way, but when you place a neutral early edge, choosing whether it merges two growing regions or walls them apart is precisely how the chain count gets nudged. The right parity plus the double-cross plays the endgame for you. A practical habit that sharpens all of this: each turn, count how many genuinely safe edges remain on the board. When the number is even, the forced concession is heading toward one player; when odd, the other. Watching that count shrink tells you several moves in advance who will have to crack first, while there is still time to change the answer.
Tips against the computer
- Scan the whole board before every move for edges that would be a third side; an accidental gift is the most common way to lose.
- Forced to concede, open the shortest chain on the board, never the longest.
- Take every box of the final chain. The sacrifice only earns its keep while another chain is still waiting.
- On the higher difficulty levels, expect the computer to know the double-cross too, and start counting chains from the first few moves.
A schoolyard game with a serious pedigree
Dots and Boxes was published in 1889 by the French mathematician Edouard Lucas, the inventor of the Tower of Hanoi puzzle, under the name la pipopipette. It has been a classroom and cafe staple ever since, while quietly ranking among the most stubborn games of its size: the Berkeley mathematician Elwyn Berlekamp wrote an entire book on its theory, The Dots and Boxes Game: Sophisticated Child's Play, and computers have fully solved only modest board sizes. The gap between how simple it looks and how deep it goes is the whole charm. A five-year-old can play it, and the five-year-old who learns the double-cross will beat the adults.
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Dots & Boxes: frequently asked questions
Why did I get an extra turn?
Completing a box always gives you another move. Strong players chain several boxes in one turn.
How does Hard play differently?
It avoids drawing the third side of a box and uses chain control to sacrifice the smallest group when forced.
Why do I get another turn after completing a box?
Completing the fourth side of a square claims it and grants an immediate extra move. Chaining these bonus turns is how you sweep a whole run of boxes at once, so setting up long chains for yourself is worth planning ahead.
What is the double-cross strategy?
When handed a chain, you take every box except the final two, then deliberately close those two off as a pair for your opponent. They must take them and open the next chain, which keeps you in control right to the end.
Should I always take a box when I can?
No. Greedily taking every available box often forces you to open the next chain and lose the exchange. Declining the last two boxes of a chain (the double-cross) usually wins you more squares overall.
What counts as a long chain?
A chain of three or more boxes linked so that opening one lets your opponent run straight through them all. Long chains decide the game; short chains and single pairs are mainly tools for passing the turn back.
What is a loop and why does it cost four boxes?
A loop is a chain of boxes that closes back on itself in a ring. Declining the end of a loop to keep control forces you to leave four boxes as two closed pairs, instead of the two you leave in an open chain. That higher price makes loops worth steering toward only when your opponent holds control.
Does board size change the strategy?
Yes. Larger grids create more and longer chains, making chain-counting and parity even more important, while small boards can come down to a single forced sacrifice. The core double-cross idea, though, works at every size.
Is Dots & Boxes free to play?
Yes. Dots & Boxes is completely free on Inkplay, with no download, no sign-up, and no in-game purchases. Open the page and play instantly on desktop or mobile.
Can I play Dots & Boxes unblocked?
Yes. Dots & Boxes runs entirely in your browser with no download, install, or plugins, so it loads instantly and keeps working even on school or work networks where bigger game sites get blocked.
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