Dots and Boxes Unblocked

Dots and Boxes looks like doodling, yet it hides one of the neatest strategy ideas in any pencil game. Each turn you add a single line between two dots. Close the fourth side of a square and you own it and draw again, which means one good line can snowball into a long streak. The catch is that most lines you draw also set up your opponent. This unblocked version is Christopher Müller’s clean black-and-white take from his PaperGames project, with a three-level AI and a local two-player mode.

Rules at a Glance

1. Choose a board of 4x4, 5x5, 6x6 or 8x8 boxes. The default is 6x6.
2. Player 1 always opens. Each turn, draw one horizontal or vertical line between two dots that sit next to each other. A line can only be drawn once.
3. If your line completes a box, the box is yours. It is stamped with a cross for Player 1 or a circle for Player 2, and you must draw another line.
4. The turn passes as soon as you draw a line that completes nothing.
5. When the grid is full, more boxes wins. An equal split is a draw.

Against the AI you may play first or second, and Undo walks back through earlier moves if you want to study a mistake.

Dots and Boxes controls

To do this	Keyboard	Mouse	Touch
Add a line to the grid	Arrow keys to reach a line, Enter to draw it	Click the gap between two neighboring dots	Tap the gap between two neighboring dots
Set up a match with the computer	—	Click "vs Computer", pick Player 1 or 2, a level and a grid size, then click "New game"	Tap "vs Computer", pick Player 1 or 2, a level and a grid size, then tap "New game"
Play someone sitting next to you	—	Click "2 Player (local)"	Tap "2 Player (local)"
Step back one move	—	Click "Undo"	Tap "Undo"
Change display and speed options	—	Click "Settings"	Tap "Settings"

Thinking in Chains

Beginners play box by box. Stronger players think about the shape of the whole board. Here is the progression most people go through.

Stage one: do not give away third sides. Any line that leaves a box with three sides drawn is a gift. Before clicking, look at both boxes that line touches.

Stage two: play safe lines as long as possible. In the opening, keep every box at two sides or fewer. The longer you can do this, the more the board’s final structure is decided by you.

Stage three: notice chains. Eventually, all safe lines run out. The board is then made of corridors of boxes, each with two sides drawn. Open one and your opponent can take the whole corridor in a row.

Stage four: sacrifice small. When you have to open something, offer the shortest chain available. A two-box chain costs you two boxes. A nine-box chain costs you the game.

On the bigger grids, keep a mental tally of how many long chains exist and how long each is. That count often settles the result many moves before the end.

How the AI Plays

The Easy computer draws random lines, so it is good for learning the rules. Medium grabs any box it can and avoids handing one over. Hard does the same and, once every line would give something away, picks the move that lets you take the fewest boxes back. Settings let you change text size, contrast, spacing and how fast the AI answers.

If you enjoy quiet two-player thinking games, Game of the Amazons also squeezes the board until someone runs out of room. You will find more in card and board games.