The sun and moon puzzle
A calm grid puzzle you solve with logic alone: place a ☀ sun or a ☾ moon in every cell so the lines stay balanced and no three alike ever touch. It's the sun-and-moon take on the classic binary puzzle — and Solsticio gives you a fresh one free every day.
Play today's board See the rules
How the sun and moon puzzle works
- Two symbolsEvery cell is either a sun ☀ or a moon ☾ — never empty in the solution.
- No three in a rowNever ☀☀☀ or ☾☾☾ in a line, across or down.
- BalanceEach row and column has the same number of suns and moons.
- One solutionAlways solvable by deduction — you never guess.
A finished board: balanced suns and moons, no three alike in any line.
Where you may have seen it
The sun and moon puzzle is the friendly face of a puzzle that also goes by Takuzu, Binairo and Tango. If you enjoyed the sun-and-moon grid elsewhere and want a daily one to keep the habit, Solsticio is built exactly for that — spoiler-free sharing, streaks, and the same board for everyone each day.
Tips to get started
Two of the same symbol next to each other force their neighbours to be the opposite. A gap between two matching symbols must be the opposite symbol. And once a line has all its suns (or all its moons), every remaining cell is decided. The full method — with worked examples — is on the how to solve page.
Questions
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Want one on your phone every day? The free Android app has hundreds of levels, streaks and reminders.