Sun & Moon

The classic binary puzzle — Takuzu / Binairo

🌗 Suns and moons in balance — never three alike, across or down!

Logic · Ages 7+

Like every game on iplay.free, Sun & Moon is completely free — no ads, no sign-up, and no downloads. It runs right in your browser, so there's nothing to install and nothing to buy. With no ads and no account, it's safe to hand to a child and easy to pick up any time.

How to play Sun & Moon

• Goal: Fill every empty square with a sun or a moon until the whole grid is full.
• How to play: Tap a square to change it: empty → sun → moon → empty. Long-press to clear it. The symbols that start on the board are clues, and they never change.
• Win: Fill the whole grid keeping all three rules. Every puzzle has exactly one answer and can be worked out step by step — you never have to guess.

Game modes

Pick the level that suits you — Sun & Moon offers 3 ways to play:

• Easy
• Medium
• Hard

Skills you'll practise

logical deduction, parity, pattern recognition, elimination.

Did you know?

🌗 One puzzle, three names: Takuzu, Binairo and simply “the binary puzzle” — every square is really a 0 or a 1. Counting suns against moons is the same odd-or-even parity check that computers make with a parity bit, the oldest trick for catching a flipped bit in stored or sent data.

Frequently asked questions

Is iplay.free really free?

Yes — every game is completely free, with no ads, no sign-up, and no downloads. There's nothing to buy and no premium tier: it's free forever.

Do I need an account or sign-up?

No. Games play instantly in the browser — no login, no email, and no personal details are ever required.

Are there any ads?

None. iplay.free runs no ad networks, so there are no banners, no pop-ups, and nothing to mis-tap — which is part of why it's safe to hand to a child.

Is it safe for kids?

Yes. Because there are no ads, no chat, and no account, there's nothing inappropriate to stumble into and no data to hand over. You can pass a device to a child without worrying about pop-ups or accidental purchases.

Do I need to download or install anything?

No. Everything runs in your web browser — there's no app to install and no updates to manage. Just open a game and play.

What devices and browsers work?

Any modern browser — Chrome, Safari, Firefox, or Edge — on a phone, tablet, laptop, or desktop, including school Chromebooks.