Connect 4
Look ahead to find threats that force your opponent’s reply.
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Strategy with Juno
Dots and Boxes Strategy Guide
Early on, look for lines that give away nothing. Once those run out, the choice is which boxes to give away and who will have to open the next chain. Juno walks through both decisions on the limestone board.
Avoid the third side
Before you draw a line, count the sides of the boxes it touches. An interior line touches two boxes. A line along the outside touches one. If your move adds a third side without scoring anywhere, your opponent can take that box and go again.
When every remaining line gives something away, look for chains. These are runs of boxes where taking one opens up the next. A loop is a chain that connects back to itself.
“Check both sides of the rail. The box you missed is usually the one your opponent takes.”
Juno
Short chains first
If you have to give something away, count how many boxes your opponent can take before they have to play elsewhere. Offering one box on its own often costs less than opening a whole row. A run of one or two boxes is a short chain.
Follow the open edges, including around corners. Boxes touching on the grid can belong to different chains if there is already a rail between them.
Chains and the double-cross
Say your opponent opens a long chain and there’s another chain elsewhere. You can take the whole first chain, but then you may have to open the next one for them.
To keep control, take all but the last two boxes. Draw the far outside edge of that pair, shown in gold. This is the double-dealing move. It scores nothing, so your opponent gets the turn. They can claim both boxes with their shared edge, the double-cross, and then they still have to open the next chain.
If this is the last chain, take all the boxes you can. In a loop, keeping control costs four boxes instead of two.
“I count what I’ll have to open after I score. Sometimes two boxes are a fair price for making that your opponent’s problem.”
Orion
The long-chain rule
A long chain has at least three boxes. In the simple case where the endgame comes down to long chains, the long-chain rule helps predict who can keep control. The mathematician Elwyn Berlekamp worked it out, and the History of Dots and Boxes tells how.
On this 36-dot board, Blue goes first and aims for an even number of long chains. Red aims for an odd number. Count connected runs as safe moves disappear. Look at whether a rail will join two runs or split one. Short chains and loops can complicate the count, so check the actual trades before committing.
Practice on LarkSpark
Start with a bot to practice spotting safe lines. Levels 1 and 2 choose any legal line. Levels 3 to 6 take available boxes. The two strongest bots also look for safe moves. You can practice the double-cross against any of them.
For a human match, join the online queue or sign in to make a private room for a friend. Check your results on the Stats page.
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