Today Sudoku contains very many types of variant Sudoku, more types of Sudoku puzzles are still under continuous development, please continue to pay attention to Sudoku today.

- Place a digit from 1 to 9 into each of the empty squares so that each digit appears exactly once in each of the rows, columns and the nine outlined 3x3 regions.
- Each number outside the grid is the sum of the first X numbers placed in the corresponding direction, where X is equal to the first number placed in that direction.
- There are some dots between cells. The numbers on each side of a dot must always be consecutive. All possible dots are marked.

- Place a digit from 1 to 9 into each of the empty squares so that each digit appears exactly once in each of the rows, columns and the nine outlined 3x3 regions.
- Each number outside the grid is the sum of the first X numbers placed in the corresponding direction, where X is equal to the first number placed in that direction.
- There are some dots between cells. The numbers on each side of a dot must always be consecutive. All possible dots are marked.

- Place a digit from 1 to 9 into each of the empty squares so that each digit appears exactly once in each of the rows, columns and the nine outlined 3x3 regions.
- If a shaded cell and a white cell are adjacent then the digit in the shaded cell is greater.

- If a shaded cell and a white cell are adjacent then the digit in the shaded cell is greater.

- Each number outside the grid is the sum of the first X numbers placed in the corresponding direction, where X is equal to the first number placed in that direction.

- Apply Classic Sudoku rules. Within each coloured region each digit must appear exactly once.

- Apply Classic Sudoku rules. Within each coloured region each digit must appear exactly once.

- Cells with circles must contain digits 1-2-3, cells with squares must contain digits 4-5-6, blank cells must contains digits 7-8-9.

- Cells with circles must contain digits 1-2-3, cells with squares must contain digits 4-5-6, blank cells must contains digits 7-8-9.

- Sujiken (from Japanese "sujikai", literally "diagonal") is a variation of Sudoku . The puzzle consists of a triangular grid of cells containing digits from 1 to 9. The objective is to fill a grid with digits so that each cell contains a digit and no digit is repeated in any column, row and diagonal in any direction. Also, no digit occurs twice in any of the three larger 3 x 3 square regions and any of the three larger triangular regions enclosed by thick borders.

- Sujiken (from Japanese "sujikai", literally "diagonal") is a variation of Sudoku . The puzzle consists of a triangular grid of cells containing digits from 1 to 9. The objective is to fill a grid with digits so that each cell contains a digit and no digit is repeated in any column, row and diagonal in any direction. Also, no digit occurs twice in any of the three larger 3 x 3 square regions and any of the three larger triangular regions enclosed by thick borders.

- Everywhere 2 odd and 2 even digits form a 2x2 checkerboard pattern, a Battenburg marking is given. A checkerboard pattern is a 2x2 area of cells where the top-left and bottom-right cells are of one type and the top-right and bottom-left cells are of another type. All possible dots are marked.

- Everywhere 2 odd and 2 even digits form a 2x2 checkerboard pattern, a Battenburg marking is given. A checkerboard pattern is a 2x2 area of cells where the top-left and bottom-right cells are of one type and the top-right and bottom-left cells are of another type. All possible dots are marked.

- A number between two cells indicates the difference of the numbers in these cells. A number between four cells indicates the difference between two diagonally adjacent cells, either top left + right bottom (\) or top right + bottom left (/). If one of the characters < or > is specified the apex of the angle points to the smaller of these numbers.

- A number between two cells indicates the difference of the numbers in these cells. A number between four cells indicates the difference between two diagonally adjacent cells, either top left + right bottom (\) or top right + bottom left (/). If one of the characters < or > is specified the apex of the angle points to the smaller of these numbers.

- Digits do not repeat along the marked diagonals.

- Digits do not repeat along the marked diagonals.

- In all cases where two digits have a consecutive value or one digit is two times as big as the other digit (or both), a greater than sign is placed. Digits have to be placed in accordance with the sign.

- In all cases where two digits have a consecutive value or one digit is two times as big as the other digit (or both), a greater than sign is placed. Digits have to be placed in accordance with the sign.

- Grey cells in the grid represent many cloned areas. Digits in these areas on corresponding positions must be identical. Cloned areas are only moved, without rotation or reflection.

- Grey cells in the grid represent many cloned areas. Digits in these areas on corresponding positions must be identical. Cloned areas are only moved, without rotation or reflection.

- Digits along each line read the same from both directions.

- Digits along each line read the same from both directions.

- Digits along each marked line are either all odd or all even.

- Digits along each marked line are either all odd or all even.

- Digits do not repeat along the marked diagonals.

- Digits do not repeat along the marked diagonals.

- Adjacent cells with digits summing to 5 are marked by V, while those summing to 10 are marked by X. Not all possible V and X are marked.

- Adjacent cells with digits summing to 5 are marked by V, while those summing to 10 are marked by X. Not all possible V and X are marked.

- The sum of the digits along the path of each arrow equals the digit in the circled cell. Digits may repeat within an arrow shape.

- The sum of the digits along the path of each arrow equals the digit in the circled cell. Digits may repeat within an arrow shape.

- A number in a squared cell indicates how many different numbers the four diagonally adjacent cells contain. A number in a circled cell indicates how many different numbers the eight orthogonally and diagonally adjacent cells contain.

- A number in a squared cell indicates how many different numbers the four diagonally adjacent cells contain. A number in a circled cell indicates how many different numbers the eight orthogonally and diagonally adjacent cells contain.

- Digits along each line are monotonically increasing or decreasing.

- Digits along each line are monotonically increasing or decreasing.

- If absolute difference between two digits in neighbouring cells equals 1, then they are separated by a white dot. If the digit is a half of digit in the neighbouring cell, then they are separated by black dot. The dot between 1 and 2 can be either white or black.

- If absolute difference between two digits in neighbouring cells equals 1, then they are separated by a white dot. If the digit is a half of digit in the neighbouring cell, then they are separated by black dot. The dot between 1 and 2 can be either white or black.

- An arrow in a cell indicates that the number in this cell is repeated at least once in the direction the arrow points to.

- An arrow in a cell indicates that the number in this cell is repeated at least once in the direction the arrow points to.