Six Dots Strategy: Avoiding Your Own Triangle and Building a Streak

Updated October 2026

Six Dots is a game of avoidance. You and the computer take turns colouring the fifteen lines between six dots, and the first to finish a triangle in their own colour loses. There is no luck in the rules and no draw is possible. This guide explains how the computer opponent actually chooses its lines, why that changes the way you should play as your streak grows, and a practical method for steering each game toward a position where the computer runs out of safe lines before you do.

The board in numbers

Six dots give fifteen possible lines and twenty possible triangles. Every line is a side of exactly four of those triangles, which is why each line you draw has consequences in several places at once. You play orange with solid lines and always move first; the computer plays blue with dashed lines and answers about half a second after each of your moves.

A line becomes "poison" for a player when that player already owns the other two sides of a triangle it would complete. Poison is personal: a line can be deadly for you and perfectly safe for the computer, or the other way round, or deadly for both. The whole game is a race to see who runs out of safe lines first.

The interface helps a lot here. When you select a dot, every other dot that would complete one of your triangles is marked with a red ring and a cross, and dots you can still connect to are highlighted as targets. The warning makes an accidental triangle easy to avoid, so in practice you lose by being left with nothing but poison. When that happens the result card says so: every line left would close one of yours.

How the computer picks its lines

Knowing the opponent's rules is the single biggest advantage you can have, so here is what the code does on each computer turn:

1. If it has no safe line left, it must draw some line, and it loses.
2. Otherwise, with a certain probability it draws a random safe line. That probability is 100 percent while your streak is zero and is multiplied by 0.82 for every win in your streak: about 82 percent at one win, 67 percent at two, 37 percent at five, 14 percent at ten and 2 percent at twenty.
3. When it does not take a random line, it consults a complete analysis of the game and draws a line that keeps it in a winning position if one exists.
4. If every safe line leads to a lost position, it picks the line that leaves it with the fewest of its own poison lines, to make your job as hard as possible.

Two facts follow. First, the computer never draws its own poison while it has a safe alternative, so you cannot win by hoping it blunders into a triangle. You win only by leaving it without safe lines. Second, the full analysis says that the player who moves second wins with perfect play, and you always move first. Against the computer at full strength you are lost from the start; every win comes from capitalising on its random moves. Early in a streak almost all of its moves are random, and later almost none are.

A simple rule that wins most early games

The most useful thing you can track is how many poison lines you are carrying. Before each move, look at the lines you could draw and, for each, count how many new poison lines for you it would create. A new poison line appears whenever your line meets one of your existing lines at a dot and the third side of that triangle is still uncoloured. Choose the line that creates the fewest.

In our simulation, a player who simply drew the safe line that left them the fewest poison lines beat the computer 73 percent of the time at a streak of zero, 35 percent at five and 14 percent at ten. That rule alone typically ends with a streak of one or two, because after the first few wins the computer's careful moves start to outnumber its random ones.

The practical form of this rule is to spread your lines across different dots. If three of your lines meet at a single dot, every pair of them makes the line joining their far ends poison, so one dot can poison three lines on its own. Lines that do not share a dot create no poison at all. A good opening sequence therefore uses lines that share no endpoints: with six dots you can draw three such lines before any two of yours have to meet.

Reading the endgame

Games are short. In our simulation they lasted between 13 and 15 lines including the losing one, so after your fourth or fifth line you are already in the endgame. At that point it pays to sort the remaining uncoloured lines into four groups:

• Safe for both. Shared lines. Whoever draws one removes it from both players' options.
• Poison for you only. The computer's private reserve: safe moves that only it can use.
• Poison for the computer only. Your private reserve: safe moves that only you can use.
• Poison for both. Dead lines. Whoever is forced to take one loses.

The principle is the same as in many counting endgames: spend the shared lines first and keep your private reserve for last. Each shared line you take is one the computer can no longer use, while your private lines will still be waiting for you after the shared ones are gone. If you draw a private line early, you have thrown away a move nobody could take from you. The counts are not frozen, because every new line can turn a shared line into poison for whoever drew it, so recount after each pair of moves. Before drawing a shared line, check that it does not convert one of your private lines, or another shared line, into poison for you.

Playing as the streak grows

Your score is the number of games you win in a row. Each win sends you straight into the next game, and the computer becomes steadily more precise. In our simulation, even a player who always chose a winning line whenever one existed and otherwise minimised their poison lines won 97 percent of games at streak zero, two thirds at streak five, about a third at streak ten and 5 percent at streak twenty. That player's streaks had a typical length of five, and only about 1.5 percent of runs reached ten.

So a realistic aim is to bank the easy early wins without carelessness, then treat every game after the fourth or fifth as a puzzle that rewards patience. When the computer is mostly accurate, your best chance is to keep the position complicated for as long as possible, with many safe lines on both sides, because each extra decision it makes is another opportunity for one of its random moves.

Controls and small details

To draw, tap one dot and then another, or press on one dot and drag to the other. Tapping your selected dot a second time clears the selection, and choosing a second dot that is already connected simply moves the selection there. The computer's most recent line glows so you can see what changed. On a keyboard, move between dots with Tab and draw with Enter or Space.

When a game ends, the losing triangle flashes and a result card appears after a short pause. After a win the card offers the next game; after a loss it offers a new run. Pressing the New button at the top during a streak ends the run on the spot and shows a final card with your streak, so use the result card's button to continue a streak. Your best streak is saved on the device. A streak above zero can be submitted to the Hall of Fame once the run is over, from the loss card or the card shown when you end the run with New; the win cards in between offer only the next game, so each run goes in once with its final streak.