Sudoku is the world's best-known number puzzle. Some cells of a 9 by 9 grid are filled in, and you complete the rest so that no digit repeats in a row, a column or a 3 by 3 box. There is no arithmetic involved, only logic and elimination, which is why it works as well for a ten-minute break as for an hour of serious thinking.
In Hamdor, Sudoku is a single-player game that works fully offline. Every grid is freshly generated with exactly one solution, so it can always be solved by logic. You get pencil notes, erase, undo and hints, with your time and mistakes shown at the top. There is also a daily challenge with a new grid each day.
How to play Sudoku
- The grid has 9 rows, 9 columns and nine 3 by 3 boxes.
- Each row, column and box must contain the digits 1 to 9 exactly once.
- The starting digits are fixed; you fill in the empty cells.
- A wrong digit stays on the board but counts as a mistake, and clashing digits turn red. Three mistakes end the game.
- The puzzle is solved when every cell holds the right digit.
These are the exact rules Hamdor plays by; the app shows them too, under each game's How to play tab.
Sudoku levels in Hamdor
- Easy: 40 starting digits, good for learning the techniques.
- Medium: 34 starting digits; most cells fall to scanning, with an occasional note.
- Hard: 30 starting digits; pencil notes become essential.
- Expert: 26 starting digits, for players who know the advanced techniques.
- Pencil notes: note mode lets you jot down the candidates in a cell. Placing a digit removes it from the notes in its row, column and box automatically.
- Hint and undo: a hint fills the selected cell with its correct digit, and undo takes back your last move.
Sudoku modes in Hamdor
- Easy
- Medium
- Hard
- Expert
Tips to solve Sudoku faster
- Start by scanning. Pick one digit, say 5, and check where it can go in each box. Rows and columns that already have a 5 rule out many cells.
- Find naked singles. If every digit but one already appears in a cell's row, column or box, that last digit is the answer.
- Look for hidden singles too. Sometimes a digit fits in only one cell of a row or box, even when that cell has other candidates.
- Use notes on harder levels. When scanning stalls, note the candidates; patterns like two cells sharing the same two candidates then stand out.
- Never guess. Every Hamdor grid can be solved by logic. If you're stuck, look at another part of the grid; each new digit gives new clues.
- Mind the mistakes. Three mistakes end the game, so note a digit first when you're not sure.
Sudoku in Hamdor
- Fully offline: once Hamdor has opened, this game runs without a connection.
- Hint and undo: stuck? The hint button shows a next move, and undo takes a mistake back.
- Stats and records: games played, games won and your best results are kept.
- Your own look: change how the table and pieces look in the Hamdor shop. It is cosmetic only and never affects who wins.
Sudoku FAQ
What are the rules of Sudoku?
Fill the 9 by 9 grid so that every row, column and 3 by 3 box contains the digits 1 to 9 exactly once.
How many levels does Hamdor's Sudoku have?
Four: Easy, Medium, Hard and Expert. Higher levels start with fewer digits on the grid.
Does every puzzle have only one solution?
Yes. Hamdor builds every grid with exactly one solution, so it can be solved without guessing.
Can I play Sudoku offline?
Yes. Sudoku works fully offline, and if you leave mid-game you can pick up where you left off.