Tango Puzzle Rules and Tips: How to Solve Sun and Moon Puzzles

Tango is a quick, satisfying logic puzzle: fill a 6×6 grid with suns and moons so that everything balances. It is closely related to puzzles known as Takuzu or Binairo, with one extra twist: = and × clues between some cells. Here are the rules and the techniques that make it easy to solve, even on hard days.

Tango rules

• Every cell holds either a sun or a moon.
• Each row and each column has exactly 3 suns and 3 moons.
• No more than two of the same symbol can sit next to each other in a row or column.
• Two cells joined by = must be the same; two cells joined by × must be different.

You can try every technique below on our free Tango puzzle, with a new daily puzzle and unlimited easy, medium and hard puzzles.

1. Pairs: block both ends

Two of the same symbol side by side can't be followed by a third. So if you see two suns together, the cells on both ends of the pair must be moons (and the other way round). This is the most common move in the whole game.

2. Sandwiches: fill the middle

A sun, an empty cell and another sun (sun, gap, sun) means the gap must be a moon, otherwise there would be three suns in a row. Look for these "sandwiches" in every row and column.

3. Count to three

Each line needs exactly three of each symbol. As soon as a row or column has three suns, every empty cell left in it must be a moon, and vice versa. Count often; this rule finishes lines quickly.

4. Follow the = and × clues

When one cell next to a clue is known, the clue tells you its neighbour straight away: = copies the symbol, × flips it. Clues also chain together: if A = B and B × C, then A and C must be different. Following chains across the grid often unlocks a whole area at once.

5. Use × pairs for counting

An × between two empty cells means that pair contains exactly one sun and one moon, even before you know which is which. That helps with counting: if a row already has two suns plus an empty × pair, the pair will add one more sun, giving three, so every other empty cell in that row must be a moon.

6. On hard puzzles, test a cell

Hard puzzles sometimes need one step of "what if" thinking. Choose an empty cell and imagine it is a sun. Follow the forced moves from the rules above. If that leads to a broken rule, such as four suns in a row or three in a line, then the cell must be a moon. This isn't guessing: you are proving the cell can't be a sun.

A simple solving routine

1. Fill the ends of every pair and the middle of every sandwich.
2. Follow every = and × clue next to a known cell.
3. Count each row and column, and complete any that have three of one symbol.
4. Repeat until nothing changes, then look for × pairs that help with counting.
5. On hard puzzles, test a single cell and see whether it breaks a rule.

Practise every day

The daily Tango is medium on weekdays and hard at the weekend, and everyone gets the same puzzle, so you can compare times with colleagues. Once you've mastered it, try Queens for a bigger logic challenge, or read our guide on how to solve Queens puzzles.