Sudokus that no one can solve, not only including Sodukus which is very difficult but also that no one trying to solve it.

17-September-2020

- 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.
- A dot between two cells indicates that the sum of the numbers in these cells is 10 or 11. If no dot between two cells the sum of the numbers in these cells must not be 10 or 11.

17-September-2020

- 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.
- A dot between two cells indicates that the sum of the numbers in these cells is 10 or 11. If no dot between two cells the sum of the numbers in these cells must not be 10 or 11.

20-September-2020

- 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.
- A dot between two cells indicates that the sum of the numbers in these cells is 10 or 11. If no dot between two cells the sum of the numbers in these cells must not be 10 or 11.

20-September-2020

20-September-2020

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

20-September-2020

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

20-September-2020

- 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.

20-September-2020

- 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.

24-September-2020

- 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.

24-September-2020

- 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.

25-September-2020

25-September-2020

29-September-2020

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

29-September-2020

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

29-September-2020

- 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.

29-September-2020

- 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.

11-October-2020

- 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.

11-October-2020

11-October-2020

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

11-October-2020

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

12-October-2020

- 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.

12-October-2020

- 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.

12-October-2020

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

12-October-2020

13-October-2020

- Digits do not repeat along the marked diagonals.

13-October-2020

- Digits do not repeat along the marked diagonals.

13-October-2020

- 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.

13-October-2020

14-October-2020

- The arrows outside the grid indicate that the nearest three digits in the corresponding direction are in ascending or descending order (the highest number is always in the direction of the arrow). All possible arrows are given, so if there is no arrow, the first three digits do not form an increasing sequence in either direction.

14-October-2020

- The arrows outside the grid indicate that the nearest three digits in the corresponding direction are in ascending or descending order (the highest number is always in the direction of the arrow). All possible arrows are given, so if there is no arrow, the first three digits do not form an increasing sequence in either direction.

15-October-2020

- Digits do not repeat along the marked diagonals.

15-October-2020

- Digits do not repeat along the marked diagonals.

15-October-2020

- The diagram is a toroid; some of the 3×3 regions don't end at the right (lower) edge of the diagram but continue at the left (upper) edge of the diagram.

15-October-2020

- The diagram is a toroid; some of the 3×3 regions don't end at the right (lower) edge of the diagram but continue at the left (upper) edge of the diagram.

15-October-2020

- 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.

15-October-2020

- 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.

16-October-2020

- Digits do not repeat along the marked diagonals.

16-October-2020

- Digits do not repeat along the marked diagonals.