Fill the grid so every row, every column and every 3×3 box holds the numbers 1 to 9 exactly once. Tap a cell, then tap a number below the board. Every board is freshly made for you, has exactly one solution, and can be solved by logic alone — no guessing.
Pick Easy, Medium or Hard. The Daily Challenge is the same board for everyone today, with its own leaderboard that resets at midnight Pacific time: Easy on Monday and Tuesday, Medium Wednesday to Friday, Hard at the weekend. If you lose a Daily you can try it again; your first finished Daily is the one that counts.
Turn on Notes (the pencil) to jot small candidate numbers in a cell. Notes clear themselves when you place that number nearby. Tapping a placed number highlights every matching number on the board.
A wrong number turns red and counts as a mistake. After 3 mistakes the game is over: restart the same puzzle or change difficulty. You get 3 hints per game; a hint fills in the selected cell (or a nearby empty one).
Pausing hides the board, and the clock stops.
Scoring: Easy is worth 1,000, Medium 2,000 and Hard 3,000. Finish fast for a time bonus of up to the same again, shrinking to nothing at 10, 20 or 30 minutes. Each mistake and each hint takes 10% off.
On a keyboard: 1–9 to place, arrow keys to move, N or Space for notes, Backspace to erase, Z to undo, H for a hint, P to pause and M to mute.
