Number Nibbles: free online sudoku with a daily challenge and parties with friends

Fill every square so each row, column and 3×3 box holds the digits 1-9 exactly once. Tap a square, then a number, or tap a number first to arm it, then paint it into squares.

Pencil marks ✏️ jot small maybe-numbers in a square; placing a real digit nearby rubs matching marks out for you.

Candies don't just fill a square. They point at the row, column or box that proves the digit, so you learn the trick.

Teacher depth 🎓 choose how much sudoku theory a candy hint may use before it simply hands you the digit.

• Just answers: no teaching, the candy quietly fills the square in
• The basics: singles, locked candidates, and pairs, triples and quads
• Clever tricks: all of the above, plus X-wings, swordfish, colouring, XY and W-wings, empty rectangles, finned X-wings and unique rectangles
• Chains: all of the above, plus jellyfish, finned big fish, X-chains, WXYZ-wings and XY-chains
• Everything: the lot, up to grouped chains and full alternating inference chains

Every tier promises exactly what it can ask of you, and never sneaks in more.

• Gentle: singles only. Every square falls to "only one number fits" or "only one home left".
• Tasty: leaner boards, plus the occasional locked candidate to spot.
• Spicy: locked candidates and naked or hidden pairs do the heavy lifting.
• Fiery: real patterns arrive: X-wings, colouring and XY-wings.
• Mighty: the deep shelf: W-wings, swordfish, empty rectangles, finned fish and unique rectangles. Never a chain.
• Legendary: chain country: X-chains, WXYZ-wings, XY-chains and alternating chains. Still never guesswork: every board yields to pure logic, and the candy can teach all of it.

Host a party and friends join with the code. Team puts everyone on one shared board with three shared hearts; Versus deals the very same puzzle to each phone, first to finish wins and three slips puts you out. Candy hints sit parties out - in a team your friends are the hints!

One shared puzzle a day, gentle on Monday and fearsome by Sunday. Fill the whole calendar for a perfect month!

Getting stuck? Look for a square with only one possible digit, or a digit with only one home in its row, column or box. The harder tiers are built so those tricks alone won't finish the job.