A lot of people think Sudoku is about being smart or good with numbers.
It is not.
Sudoku is really about staying calm, paying attention, and following simple rules. Once you understand how to look at the board properly, the puzzle starts to solve itself.
When I was younger, my dad travelled and I asked him to buy me video games.
Instead, he came back with an electronic Sudoku game.
I was disappointed at first. It was not what I asked for, and I did not even know how to play it. But after some time, curiosity kicked in and I decided to read the manual that came with it.
That manual changed everything.
It did not teach anything complicated. It simply explained the rules clearly and showed how to apply them patiently. Once I understood those rules, Sudoku stopped feeling hard.
Try it yourself
Want to practice what you just learned? Try the Sudoku app and apply these rules in real-time.
The rules
Sudoku has only three rules.
| Where | What must happen |
|---|---|
| Row | Numbers 1 to 9 appear once |
| Column | Numbers 1 to 9 appear once |
| Box (3×3) | Numbers 1 to 9 appear once |
That is all.
Any move that breaks one of these rules is wrong. There are no exceptions.
Rule one: Find what is missing
Let us look at a simple example.
| 1 | 2 | 3 | | 5 | 6 | 7 | | 9 |
Two spaces are empty in this row.
First, list the numbers that are already there.
| Numbers present |
|---|
| 1, 2, 3, 5, 6, 7, 9 |
Now list the numbers that are missing.
| Numbers missing |
|---|
| 4, 8 |
This tells us something important. Each empty space must be either 4 or 8.
We do not choose yet. We look for more information.
Rule two: Check the column
Now focus on one of the empty spaces and look at its column.
| Column numbers |
|---|
| 1, 3, 5, 8 |
This column already has 8.
So that empty space cannot be 8. The only option left is 4.
Once that is placed, the remaining empty space automatically becomes 8.
This is how Sudoku works. No guessing. Just checking the rules.
Rule three: Use the box
Now let us look at a 3×3 box.
| 2 | 3 | |
|---|---|---|
| 4 | 5 | 6 |
| 7 | 8 | 9 |
Only one number is missing here.
List what you already see.
| Numbers present |
|---|
| 2, 3, 4, 5, 6, 7, 8, 9 |
The missing number is 1.
So the empty space must be 1.
These are the easiest moves in Sudoku, and you should always look for them first.
When you are not sure, write down choices
Sometimes a space can take more than one number.
That is normal.
| Row | Column | Possible numbers |
|---|---|---|
| A | 4 | 2 or 7 |
When this happens, do not rush to choose.
Just remember:
- The space can only be 2 or 7
- Every other number is wrong
This information will become useful later as the board changes.
The most important rule: Do not guess
If you are not sure, stop.
Sudoku does not reward guessing. It rewards patience.
Good players do not force moves. They:
- Check another row
- Look at a different column
- Find an easier box to solve first
The board will always give you a clear move if you look carefully.
Every proper Sudoku puzzle has a solution.
If you:
- Follow the rules
- Avoid guessing
- Check rows, columns, and boxes carefully
Sudoku is not really about numbers.
It is about learning to slow down, observe carefully, and trust simple rules.
If you can do that, you are already good at Sudoku.
The rest is just practice.