Prime Directive
(Published on 15. April 2023, 15:35 by DiMono)
Normal sudoku rules apply.
Digits in killer cages do not repeat and must sum to a prime number. 1 is NOT a prime number!
Boxes are numbered in reading order (top left is box 1, top middle is box 2, and so on). Cells within a box are numbered the same way.
Shade one cell in each row, column, and box. The position of the shaded cell will be indexed by the first digit in its row, column, and box. i.e. if R2C3 is shaded, then R1C1 will be 6, R1C3 will be 2, and R2C1 will be 3.
Shaded cells in prime-numbered boxes (2, 3, 5, 7) contain the box number.
The highlighted cells, read in box order, must also be a prime number.
Solve on SudokuPad
Digits in killer cages do not repeat and must sum to a prime number. 1 is NOT a prime number!
Boxes are numbered in reading order (top left is box 1, top middle is box 2, and so on). Cells within a box are numbered the same way.
Shade one cell in each row, column, and box. The position of the shaded cell will be indexed by the first digit in its row, column, and box. i.e. if R2C3 is shaded, then R1C1 will be 6, R1C3 will be 2, and R2C1 will be 3.
Shaded cells in prime-numbered boxes (2, 3, 5, 7) contain the box number.
The highlighted cells, read in box order, must also be a prime number.
Solve on SudokuPad
Solution code: The 9 digit prime number from the highlighted cells, followed by row 6 (18 digits)
Last changed on on 3. January 2026, 22:39
Solved by Bootenks, Migu, amarins, TheRiddler, keerdelta, Vebby, hAndyman, CrippledLamp, PrimeWeasel, AKernel, ademjaz, tess, Felis_Timon, Sewerin, SashaBu
Comments
on 3. January 2026, 22:38 by DiMono
Rewrite rules for extra clarity. Updated to just a better SudokuPad link.
on 16. April 2023, 03:03 by TheRiddler
Very cool puzzle. Nice opening logic and smooth solve afterwards, although the end required some careful pencil-marking and was a bit tricky for me.
on 15. April 2023, 17:01 by Bootenks
Thank you for creating this nice puzzle. My brain is still in the mode to check if digits sum to a prime number. :D
