Normal Sudoku: Fill the grid with digits 1–9 such that every row, column, and 3 by 3 box contains each digit exactly once.
The Tenth Box: The nine center cells of the standard 3 by 3 boxes form a "Tenth Box" which must also contain the digits 1–9 without repetition.
Any rule or constraint in a standard 3 by 3 box is applied to the corresponding cells in the Tenth Box. Constraints map from the nine standard boxes to the Tenth Box, but not vice-versa.
Killer Cages: Digits in a cage must sum to the value in the top-left corner. Digits cannot repeat within a cage.
Black Dot: If two adjacent cells are separated by a black dot, one number must be exactly double the other.
White Dot: If two adjacent cells are separated by a white dot, the two numbers must be consecutive.
Red dot: If two adjacent cells are separated by a red dot, they must have different parity.
Example: In this puzzle, the fourth and fifth cells in Box 1 are inside the cage of sum 11. This means that the sum of the digits in cells R2C1 and R2C2 is 11. Furthermore, the sum of the digits in the fourth and fifth cells of the Tenth Box (R5C2 and R5C5) is also 11.
Example: In this puzzle, a red dot sits between the second and fifth cells of Box 1. This means that the digits in R1C2 and R2C2 have different parity. Furthermore, the second and fifth cells of the Tenth Box (R2C5 and R5C5) also have different parity.
Solution code: Row 9 (left to right)
on 3. June 2026, 21:34 by AaronH
Hardest of these so far for me. Really love the concept and execution.
| Difficulty: | ![]() |
| Rating: | N/A |
| Solved: | 7 times |
| Observed: | 1 times |
| ID: | 000SYC |