-The rules of Jigsaw Sudoku are similar to standard Sudoku, since you must place each of the numbers 1 to 9 (or 1 to whatever the size of the puzzle is) into each of the rows and columns. However whereas standard Sudoku also has rectangular boxes that must each contain every number, in Jigsaw Sudoku these boxes are replaced by different bold-lined shapes that must each contain every number instead.-In Non-Consecutive Sudoku no two adjacent cells have consecutive values. For example, if a cell contains 3, then any neighbouring square cannot contain either 2 or 4.Fill in the empty cells, one number in each, so that each column, row, and region contains the numbers 1 through 9 exactly once.-Kropki Sudoku puzzles add black (o) and white (o) circles to a regular Sudoku puzzle. All pairs of touching squares which contain consecutive values (such as 2 & 3 or 6 & 7) are marked with a white circle: o. Also, all pairs of touching squares which contain values where one number is exactly twice the value of the other (such as 2 & 4, or 4 & 8) are marked with a black circle: o. This applies to left/right, up/down touching only - there are no diagonal markers. All possible o and o are given, so if there is no circle between two touching squares then they are not consecutive and one is not double the value of the other.-The Sudoku Chain is similar to the Jigsaw Sudoku, each one have regions of irregular shapes.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 digits appear exactly once in each row, column and chain.