Dots and Boxes is a quiet game of lines. A grid of dots is on the table, and you and the computer take turns drawing one line between two neighboring dots. Close the fourth side of a box and it is yours, and you draw again. The player with more boxes at the end wins.

How to play

Tap the gap between two neighboring dots to draw a line there. On a computer, click it. Then the computer draws one, and you take turns.

When your line finishes the fourth side of a box, you win that box and you draw again. Your boxes are marked with a circle, and the computer's boxes show a diamond. The game ends when every line has been drawn, and the player with more boxes wins.

The computer waits a short moment before each of its lines, so you can follow what it does. Before the first line, you choose who goes first.

A move can finish two boxes at once, and a single move can lead to a long run of turns, which is where the game gets exciting.

The levels

The level sets the size of the board and how well the computer plays.

Easy: a 3 by 3 board of boxes. The computer often gives boxes away.
Medium: a 4 by 4 board. The computer never draws a third side of a box unless it has to. A 4 by 4 game can end level.
Hard: a 5 by 5 board. It plays the long chains and knows when to turn down boxes on purpose.
Expert: a 5 by 5 board. It plans the whole ending and tries every line.

The 3 by 3 and 5 by 5 boards have an odd number of boxes, so those games can never end in a tie.

Today's game

There is a Medium game each day, a 4 by 4 board, built from the same seed for everyone. A game you leave unfinished is kept on your device.

Tips

At the start there are many safe lines. A safe line is one that does not draw a third side of any box. Use them up carefully.
Never draw the third side of a box unless you have to. The computer will close it and then get another turn.
Always take a free box when one is offered, with one big exception: see the next tip.
When the safe lines run out, somebody has to open a chain of boxes. A good trick is to take all the boxes in a chain except the last two, and give those two away with a single line. The opponent takes the two and then must move first into the next chain. You keep control.
When you are forced to open a chain, open the shortest one first. A chain of one or two boxes costs you little, and the long chains are worth more later.
Count the chains before the safe moves are all gone. If you can make the number work in your favour, you will be the one who does not have to open the first long chain.
Do not be afraid to lose a few boxes to gain more later. The final score is what counts.

A bit of history

Mathematicians have studied Dots and Boxes for well over a century, and it is a good example of a game that is simple to learn but deep.

Questions

Why do I get another turn? Because you finished a box. Keep drawing until a line does not finish one.

Can the game end in a tie? Only on the 4 by 4 board. The odd-sized boards always have a winner.

What does a diamond mean? It marks a box the computer has won. Your own boxes are shown with a circle.

Who goes first? You choose when you start a game.

Dots and Boxes