# Sudoku rules

Sudoku are easy to learn yet highly addictive language-independent logic puzzles which have recently taken the whole world by storm. Using pure logic and requiring no math to solve, these fascinating puzzles offer endless fun and intellectual entertainment to puzzle fans of all skills and ages.

The Classic Sudoku is a number placing puzzle based on a 9x9 grid with several given numbers. The object is to place the numbers 1 to 9 in the empty squares so that each row, each column and each 3x3 box contains the same number only once.

Sudoku puzzles come in endless number combinations and range from very easy to extremely difficult taking anything from five minutes to several hours to solve. Sudoku puzzles also come in many variants, each variant looking differently and each variant offering a unique twist of brain challenging logic.

However, make one mistake and you’ll find yourself stuck later on as you get closer to the solution… Try these puzzles, and see if you can solve them too!

## Classic Sudoku

Each puzzle consists of a 9x9 grid containing given clues in various places. The object is to fill all empty squares so that the numbers 1 to 9 appear exactly once in each row, column and 3x3 box.

## Mini Sudoku

Each puzzle consists of a 4x4 or 6x6 grid containing given clues in various places. The object is to fill all empty squares so that the numbers 1 to 4 (for 4x4 puzzles) or 1 to 6 (for 6x6 puzzles) appear exactly once in each row, column and box.

## Mega Sudoku

Each puzzle consists of a 12x12 or 16x16 grid containing given clues in various places. The object is to fill all empty squares so that the numbers 1 to 12 (for 12x12 puzzles) or 1 to 16 (for 16x16 puzzles) appear exactly once in each row, column and box.

## Irregular Sudoku

Each puzzle consists of a 6x6, 9x9 or 12x12 grid containing given clues in various places. The object is to fill all empty squares so that the numbers 1 to 6 (for 6x6 puzzles) or 1 to 9 (for 9x9 puzzles) or 1 to 12 (for 12x12 puzzles) appear exactly once in each row, column and irregular shaped box.

## Diagonal Sudoku

Each puzzle consists of a 9x9 grid containing given clues in various places. The object is to fill all empty squares so that the numbers 1 to 9 appear exactly once in each row, column, diagonal and 3x3 box. In the case of Diagonal Sudoku with Odd or Diagonal Sudoku with Even, the rules should comply with OddEven Sudoku as well.

## Multi Sudoku

Each puzzle consists of two or more Sudoku grids overlapping each other in various configurations. The grids may be Classic Sudoku or a mix of different Sudoku variants. The object is to solve all grids according to their variant rules. Note that overlapping areas comply with the rules of more than one grid.

## Sum Sudoku

Each puzzle consists of a 9x9 Sudoku grid containing areas surrounded by gray or dotted lines. The object is to fill all empty squares so that the numbers 1 to 9 appear exactly once in each row, column and 3x3 box, and the sum of the numbers in each area is equal to the clue in the area’s top-left corner. In addition, no number may be used in the same area more than once.

## OddEven Sudoku

Each puzzle consists of a 9x9 grid containing given clues in various places, and one or more of the given clues are located in gray squares. The object is to fill all empty squares so that the numbers 1 to 9 appear exactly once in each row, column and 3x3 box, and all gray squares contain either odd or even numbers according to the given clues.

## Picture Sudoku

Each puzzle consists of a 9x9 grid containing given clues in various places. The object is to fill all empty squares so that the numbers 1 to 9 appear exactly once in each row, column and 3x3 box.

## Chain Sudoku

Each puzzle consists of a group of circles arranged in a square grid and containing given clues in various places. The object is to fill all empty circles so that the numbers 1 to 4 (for 4x4 puzzles), 1 to 5 (for 5x5 puzzles) etc. appear exactly once in each row, column and chain.