A Touch of Difference
(Published on 2. October 2026, 17:07 by varepsilon)
Normal Sudoku rules apply: Place the digits 1–9 exactly once in every row, column, and 3×3 box.
Difference Regions: Divide the entire grid into orthogonally connected regions, each containing exactly one circle. The circled digit equals the number of cells in its region. Digits may not repeat within a region.
Any two orthogonally adjacent regions with circled digits X and Y must share exactly |X − Y| (larger minus smaller) unit cell edges in total. Count all shared edges, even if they form separate sections.
The following image shows a sample 6×6 puzzle and its solution with the same rule set.
Play 6×6 on SudokuPad: https://sudokupad.app/3vpxo3pctq
Solution code: Row 3 from left to right, with each digit followed by the size of its region. For example, the 6×6 puzzle gives:
633646562515
Comments
on 6. October 2026, 12:42 by varepsilon
Removed the brackets in the solution code
on 6. October 2026, 11:06 by MonsieurTRISTE
The solution code is bad. At least remove the brackets since they don’t make a difference.
on 3. October 2026, 23:19 by palletpusher
Brilliantly set, varepsilon! The region building required some very novel logic which I quite enjoyed. Didn't understand the 5* difficulty till I arrived at the sudoku which followed. Just under two hours for me. Loved this; thank you
varepsilon: Thank you for playing!
on 2. October 2026, 22:35 by Hohig
Amazing puzzle, every time I found something and thought now its going to break, nope. Every step was a hard fought deduction.
