The goal

Fill the 9×9 grid so that every row, every column, and every 3×3 box contains each digit 1 through 9 exactly once. The bold numbers are given clues and cannot be changed. Every puzzle has exactly one solution that can be reached by logic alone — no guessing needed.

Entering numbers

• Select a cell by clicking or tapping it. Its row, column, and box are highlighted, along with any cells holding the same number.
• Enter a digit by tapping 1–9 below the grid or pressing 1–9 on your keyboard.
• Erase with the Erase button, Backspace, Delete, or 0. Entering the same digit again also removes it.
• Move around with the arrow keys; press Esc to deselect.
• When all nine of a digit are placed, its button below the grid grays out.

Pencil marks (notes)

• Toggle pencil mode with the ✏️ button or the P key.
• In pencil mode, digits are written as small candidate notes in the corner positions of an empty cell — press a digit again to remove it.
• Entering a real number clears that cell’s notes. Notes in other cells are left for you to manage — tidy as you go!
• Auto Candidate Mode (checkbox under the number pad) fills every empty cell with all digits that don’t currently conflict, and updates as you play. Turn it off anytime to prune the notes yourself.

Finishing

• The timer starts when the puzzle opens and stops when you solve it — your time is shown in the victory screen.
• When the grid is full, incorrect entries are highlighted in red so you can fix them.

Daily puzzles

Three fresh puzzles — Easy (~38 clues), Medium (~30), and Hard (~25–28) — are published every morning. Miss a day? Visit the archive to play past puzzles.