Granite Puzzles · Sudoku
Notch Sudoku
Four new sudoku puzzles every day, one at each level, named for White Mountain notches from Pinkham to Dixville. Everyone gets the same four on the same New Hampshire date. Practice puzzles are there whenever you want more, and your progress stays on your device.
Loading Notch Sudoku…
Keyboard
| 1 to 9 | Fill in the selected square |
| Shift + 1 to 9 | Add or remove a note |
| N | Turn notes on or off |
| Backspace or 0 | Clear the square |
| Arrows | Move around the grid |
| U or Ctrl + Z | Undo |
How to play
Tap a square, then tap a number on the pad below the grid. Turn on Notes to pencil in the numbers a square could still be, and tap a note's number again to take it out. Undo steps back one move at a time, and Hint fills in a square when you're stuck.
- The puzzle
- Fill the grid so that every row, every column and every 3×3 box holds the numbers 1 to 9 once each. Every puzzle has exactly one solution, and you can reach it by logic alone, with no guessing.
- Levels
- Easy puzzles need only singles: a square with one number left, or a number with one place left in a row, column or box. Medium adds pointing numbers and pairs, Hard adds triples and the X-wing, and Expert can need a swordfish or an XY-wing.
- Daily and practice
- The daily puzzles change at midnight in New Hampshire, and everyone gets the same four. Practice puzzles are numbered, so you can go back to one you left unfinished or start a new one at any level.
- Notes and mistakes
- Placing a number takes it out of the notes in its row, column and box. With Show mistakes on, a wrong number turns red and counts as a mistake. Turn it off to solve with no checking at all.
- Hints and the clock
- A hint fills the selected square with the right number. With no square selected, it fills the square a careful solver would fill next. The clock starts with your first move, stops while the tab is in the background, and stops for good when the grid is complete.