STEKIUS
Sudoku online at STEKIUS: from Easy to Expert
Play nowSudoku is the best-known number puzzle in the world. It needs no sums at all, only logic: every row, every column and every box must have all the numbers from 1 to 9, once each. It starts easy and becomes more and more demanding.
At STEKIUS you play Sudoku online for free, on a realistic grid, on four levels, from Easy to Expert. You have pencil notes, undo, an eraser and one hint in every game. Below you will find all the rules, how the mistakes count and how you win chips.
The grid and the aim
The grid has 81 squares (9×9), divided into nine 3×3 boxes. Some numbers are given from the start and do not change. You fill in the rest.
There is only one rule: every row, every column and every box must have each number from 1 to 9 exactly once. You do not need to guess: with care and logic, every number finds its place.
How you place a number
You tap an empty square and then a number. If the number is right, it stays in place. If it is wrong, it turns red, counts as a mistake and is erased.
That way you can never carry on with a wrong number that would ruin the whole grid, but every mistake has a cost.
Four levels
Sudoku has four levels: Easy, Medium, Hard and Expert. You choose the level before you start, and the higher you go, the more thinking the puzzle needs.
The mistakes allowed depend on the level: three on Easy and Medium, four on Hard and Expert. When you reach them, the game is lost. Every level also has its own time limit, and when it runs out, the game is lost.
Notes, undo and the hint
With notes you write small numbers in pencil in a square, for everything that could go there. This is how experienced players solve hard Sudoku puzzles. Undo and the eraser work on your notes.
In every game you also have one hint. It does not solve the grid for you; it shows you the next number that can be found with logic, so that you get unstuck.
Chips
Every level has its own stake and its own prize in virtual chips. A win pays its chips, while a loss costs the stake. Wins give chips up to a limit each day; after that you can keep playing for free, just for the joy of the puzzle.
On a phone and a computer
The grid is made to play comfortably on a phone screen too: you tap a square with your finger and then one of the number buttons. On a computer everything is done with the mouse. Sudoku is played on your own, so you can start a game whenever you have a few minutes.
Why Sudoku is worth playing
Sudoku trains concentration, logic and patience. You do not need to be good at maths: the numbers are just symbols, and they could be letters or colours. With the four levels, you start from the easy ones and move up as you improve.
Leaving
Leaving is free only in the first seconds, before you place three numbers. After that, leaving costs the stake and a leave penalty.
Tips
- Start with the rows, columns and boxes that already have many numbers.
- For each number, look for the one square in a box where it can only go.
- On the hard levels, use notes early.
- Keep the hint for the moment you are really stuck.
Questions
How many levels does Sudoku have?
Four: Easy, Medium, Hard and Expert.
How many mistakes are allowed?
Three on Easy and Medium, four on Hard and Expert.
What does the hint do?
It shows the next number that can be found with logic. There is one in every game.
Can I write notes?
Yes, small numbers in pencil in every square. Undo and the eraser work on them.
