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.
- 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.

- 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.
- 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.

- 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.
- The connected shaded cells contain each digit from 1 to 9.

- The connected shaded cells contain each digit from 1 to 9.

- Some intersections of the grid lines are marked by a number and an operator (+, -, x, /) in a circle. The number is the result of the operation, applied to both pairs of diagonally opposite cells. An E in the circle indicates that all four adjacent digits are even, while an O indicates that all four adjacent digits are odd.

- Some intersections of the grid lines are marked by a number and an operator (+, -, x, /) in a circle. The number is the result of the operation, applied to both pairs of diagonally opposite cells. An E in the circle indicates that all four adjacent digits are even, while an O indicates that all four adjacent digits are odd.

- 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.

- 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.

- A number at the edge of the diagram indicates the difference between the highest and the lowest number in the first three cells in the corresponding row or column.

- A number at the edge of the diagram indicates the difference between the highest and the lowest number in the first three cells in the corresponding row or column.

- One of the numbers in the four cells around a dot is the num of the other three numbers.

- One of the numbers in the four cells around a dot is the num of the other three numbers.

- Digits along each line are monotonically increasing or decreasing.

- Digits along each line are monotonically increasing or decreasing.

- The digits in two orthogonally adjacent cells cannot have a sum of either 5 or 10.

- The digits in two orthogonally adjacent cells cannot have a sum of either 5 or 10.

- There are some dots between cells. The numbers on each side of a dot must always be consecutive. Not all possible dots are marked.
- Digits outside the grid indicate the sum of the first 3 digits in the corresponding direction.

- There are some dots between cells. The numbers on each side of a dot must always be consecutive. Not all possible dots are marked.
- Digits outside the grid indicate the sum of the first 3 digits in the corresponding direction.

- Digits do not repeat along the marked diagonals.

- Digits do not repeat along the marked diagonals.

- There are some dots between cells. The numbers on each side of a dot must always be consecutive. All possible dots are marked.

- 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.

- There are some dots between cells. The numbers on each side of a dot must always be consecutive. Not all possible dots are marked.

- 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.

- Each set of four digits in the intersection of two lines indicates the digits that have to be placed in the four adjacent cells.

- Each set of four digits in the intersection of two lines indicates the digits that have to be placed in the four adjacent cells.

- Consider each number to be the height of a building. The numbers outside the grid indicate how many buildings can be seen when looking in that direction (taller buildings conceal smaller buildings behind them).

- Consider each number to be the height of a building. The numbers outside the grid indicate how many buildings can be seen when looking in that direction (taller buildings conceal smaller buildings behind them).

- Each set of four digits in the intersection of two lines indicates the digits that have to be placed in the four adjacent cells.

- Identical digits do not touch each other diagonally.

- Identical digits do not touch each other diagonally.

- Digits have to be place in accordance with the “greater than” signs.
- Digits outside the grid indicate the sum of the first 3 digits in the corresponding direction.

- Digits have to be place in accordance with the “greater than” signs.
- Digits outside the grid indicate the sum of the first 3 digits in the corresponding direction.

- 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.