Full House
- Column 2: only one cell is empty.
- Column 2: the only missing number is 7.
How to play sudoku
Sudoku has one rule, and it takes no arithmetic. Here are the rule, three ways to find a number that are enough for the easier levels, and how the game in Telegram helps along the way.
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The goal
Fill every empty cell with a number from 1 to 9 so that each row, column and 3×3 box holds every number once. The numbers given at the start allow exactly one solution.
Three ways to find a number
These three techniques are all the easier levels ask for. Each is shown on a real puzzle, in the words of the game's hint.
Naked Single
- Look at the numbers in the row, column and box of this cell.
- Every number except 8 is already used there.
- So this cell must be 8.
Playing in Telegram
Entering numbers
Select a cell, then tap a number. A wrong number turns red and counts as a mistake.
Notes
Turn on Notes to add or remove small candidate numbers. Placing a number clears it from the notes in its row, column and box.
Undo and Erase
Undo takes back your last step. Erase clears a wrong number or the notes of the selected cell.
Hints
Each game has one hint. It shows the next step and explains why it works.
Mistakes
A number that does not match the solution is a mistake: it turns red, earns nothing and stays counted even after you undo or erase it. With the mistake limit on, the third mistake ends the game.
Difficulties
The first two difficulties are open from the start. Each harder one unlocks after enough wins at the one before it; the difficulty list shows how many wins are left.
Do you ever have to guess?
No. Every puzzle in the game has exactly one solution and can be solved by logic alone. When no number is obvious, a technique finds the next step, and the hint shows which one.
Tips for a first puzzle
- Start with the rows, columns and boxes that are nearly full.
- Notes help you keep track of the numbers a cell can still hold.
- If a number fits in only one cell of a box, it goes there.
- Stuck? The hint explains the next step before it places a number.
What to learn next
The harder levels call for more than these three: pairs and triples, pointing, X-Wing and others. Each is shown on a real puzzle, with a puzzle to practice it on.