- 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.
- Digits have to be place in accordance with the “greater than” signs.

- 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.
- Digits have to be place in accordance with the “greater than” signs.

- 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.
- 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.

- A number between two cells indicates the product of the numbers in these cells. A number between four cells indicates the product between two diagonally adjacent cells, either top left + right bottom (\) or top right + bottom left (/).

- A number between two cells indicates the product of the numbers in these cells. A number between four cells indicates the product between two diagonally adjacent cells, either top left + right bottom (\) or top right + bottom left (/).

- A dot between two cells indicates that the digits in the two cells form a double digit square number in the reading direction. there are no square numbers marked by a dot.

- A dot between two cells indicates that the digits in the two cells form a double digit square number in the reading direction. there are no square numbers marked by a dot.

- Digits do not repeat along the marked diagonals.

- Digits do not repeat along the marked diagonals.

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

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

- 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.

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

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

- 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.

- 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.

- 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.

- Cells with shaded squares contain even digits. Cells with shaded circles contain odd digits.

- Cells with shaded squares contain even digits. Cells with shaded circles contain odd digits.

- 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.

- 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.

- 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.

- Sum and difference of two orthogonally adjacent numbers must not be 5.

- Sum and difference of two orthogonally adjacent numbers must not be 5.

- 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.

- 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.

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

- 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 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.