Sun & Moon – a calm logic puzzle with two symbols
Sun & Moon is a small grid puzzle that feels like Sudoku's relaxed cousin. You only use two symbols, a sun and a moon, but every placement has to follow three simple rules. A puzzle takes two to ten minutes, and every one has exactly one solution that you can reach by pure logic – no guessing needed.
This kind of puzzle is also known as a binary puzzle, Takuzu or Binairo, and it became very popular again as a daily game on LinkedIn. Our version has 60 levels in three difficulties and a new puzzle every day.
Quick start in 3 steps
- Tap an empty cell once for a ☀️ sun, twice for a 🌙 moon, three times to clear it.
- Follow the rules: 3 suns and 3 moons per row and column, never three of the same in a line, and obey the = and × signs.
- Fill all 36 cells without breaking a rule and the puzzle is solved.
The full rules
Setup
The board has 6×6 cells. Some cells are already filled – they have a grey background and can't be changed. Some borders between two cells show a sign.
The three rules
- Balance: every row and every column has exactly 3 suns and 3 moons.
- No three in a line: you can't have three suns or three moons next to each other, across or down. Two is fine.
- Signs: = between two cells means they hold the same symbol. × means they are different.
How a move works
Tap to cycle: empty → sun → moon → empty. If something breaks a rule, the cells turn red and the message line tells you which rule it is.
When you win
When all 36 cells are filled and no rule is broken, you have found the one solution.
When you are stuck
If the board is full but red cells remain, the game tells you. Use Undo, or press Hint – it first points out a wrong cell, and if all your cells are right, it fills a cell that is forced by the rules.
Buttons and numbers
| Button / number | What it means |
|---|---|
| ↶ Undo | Takes back your last tap. Free and unlimited. |
| 💡 Hint | Shows a wrong cell, or fills one correct cell. Free. |
| ⟲ Clear | Removes everything you placed. Puzzle cells stay. |
| ⏭ Skip | Opens the next level. Free. |
| ▦ Levels | All 60 levels with your stars. |
| Level / Mode | Your level and its difficulty. 📅 is the daily puzzle. |
| Filled | How many of the 36 cells are filled. |
| Time | Starts with your first tap. Pauses when you leave the tab. |
Levels
- Easy (1–15): 14 cells already filled and 7 signs.
- Medium (16–40): 9 filled cells and 6 signs.
- Hard (41–60): as few filled cells as possible and only 5 signs. You need the signs and longer chains of logic.
- 📅 Daily: Medium or Hard, new every day, the same for everyone.
Every puzzle was checked by a solver to have exactly one solution.
Stars
- ★★★ – solved with no hint
- ★★ – 1 or 2 hints
- ★ – more hints
6 tips
- Two in a row? Close both ends. If you see ☀️☀️, the cells on both sides must be moons.
- Fill the gap. In ☀️ _ ☀️ the middle must be a moon.
- Count. When a row already has 3 suns, all its other cells are moons.
- Use the signs in chains. If A = B and B × C, then A × C. Signs often decide a whole corner.
- Test the last two cells. When a row needs one more sun and one more moon, try each way in your head. Often one way makes three in a line, so the other way is right.
- Don't guess. Every puzzle can be solved with logic. If you can't find a sure move, look at a different row or column.
A little history
Binary puzzles appeared in puzzle magazines in Europe in the late 2000s under names like Takuzu, Binairo and Tohu-wa-Vohu. In the Netherlands and Belgium they became a newspaper classic next to Sudoku. The sun and moon version with = and × signs became widely known when LinkedIn added it as a daily game in 2024.
What does it do for your brain?
To be honest, it won't make you smarter overnight. But it is good light training for:
- Logical deduction – "if this, then that".
- Pattern spotting – pairs, gaps and counts jump out after a few games.
- Patience – you learn to wait for a sure move instead of guessing.
- Focus – one short, quiet task with a clear end.
What this game can and can't do
- ✅ Runs in your browser. No download, no account.
- ✅ Every puzzle has exactly one solution. Undo, Hint and Skip are free, with no ads in front of them.
- ✅ Open levels, stars and your current board are saved in this browser.
- ❌ No sync between devices. Clearing browser data resets progress.
- ❌ The game shows broken rules right away – there is no "hard mode" without help yet.
Frequently asked questions
What are the rules of Sun and Moon?
Every row and column has 3 suns and 3 moons, you can't have three of the same next to each other, and cells joined by = are the same while cells joined by × are different.
Does every puzzle have only one solution?
Yes. Every puzzle was checked by a solver to have exactly one solution, so you never need to guess.
What does the × sign mean?
The two cells next to the × must hold different symbols: one sun and one moon.
Can I have two suns next to each other?
Yes, two is fine. Only three of the same in a row or column is not allowed.
Is this the same as LinkedIn Tango?
It uses the same well-known binary puzzle rules. Our game is a separate free game with its own puzzles, levels and daily puzzle.
How does the Hint work?
If one of your cells is wrong, the hint marks it. If all your cells are right, it fills one cell that the rules force.
How do I get 3 stars?
Solve the puzzle without any hint. Undo and Clear do not cost stars.
Where is my progress saved?
In your own browser on this device. If you clear your browser data or use another device, you start again.
Is there a new puzzle every day?
Yes. Tap Daily for a new Medium or Hard puzzle every day. It is the same for everyone.