# Sudoku

Sudoku is a number puzzle that has been challenging the reign of crosswords as one of the most played classic puzzle games worldwide. Unlike the latter, it does not require any previous or specific knowledge. Everything depends on logic and sound reasoning, which makes Sudoku puzzles suitable for all ages.

## Sudoku Rules

Sudoku is a puzzle played traditionally with a 9x9 grid, which is further divided into 9 groups of 3x3.

The rules of the game are very simple:

- The players must complete a partially filled 9x9 grid with the numbers from 1 to 9, taking care not to repeat any digit per column, row, and group.

- There is only one possible solution for each puzzle.

## How to play

Start by choosing the level of difficulty you want to challenge: Easy, Medium, Hard, Evil, or Impossible. The difficulty of Sudoku puzzles is not linked to the size of the grid or how filled it is but rather to the position of the numbers already present in the grid at the beginning of the game.

Once you have chosen which difficulty mode to play, you can finally begin. Click on the cell you want to fill in and use the digital number pad on the screen or your own physical keyboard to type it in.

## Sudoku features

This game of Sudoku online features some options that allow for some customization of the play mode.

Check for solution: this option is turned off by default. When it is on, the mistakes in the grid will turn red. You can switch it on and off throughout the game to check your progress.

Notes: turn this feature on to note down the candidates for each cell. The notes are colored to make it easier to identify the numbers. They are also automatically updated every time you commit to a number in the grid.

Hint: this button will reveal the solution for one cell of your choice. Select the cell first and then click on the Hint button. There is no limit to the number of hints you can use in a puzzle.

## Sudoku Tips

### Check for Naked Singles

Note down the candidates for all cells. If a cell has only one possible candidate that is its solution.

### Check for Naked pairs

Write down all candidates for each cell. A Naked Pair happens when two cells on one row, column, or group have the same pair of candidates and no others. The solution for those cells must be one of those two digits which means that they cannot be candidates in any other cell in the same row, column, or group.

### Keep an eye out for changes in the grid

Writing down the solution for one cell can unlock several possibilities in other areas of the grid. Make sure to always check if your notes have been updated. Pay also close attention to the row, column or group immediately affected by the number you wrote down.

### Do not try to guess

There is no place for guesses or luck in Sudoku. It is a game of pure logic. Trying to guess a number and failing can lead to an unsolvable puzzle. Moreover, players usually do not realize their mistake until much later in the game when they think they are about to finish, which makes the situation all the more frustrating.

## Developed by

This game was developed by Appgeneration. You can also play this Sudoku game at their website and enjoy a greater variety of features and game options including Sudoku for kids, daily challenges, and a blog with tips and strategies to become a Sudoku master.