• Normal Sudoku rules apply.
• Disjoint Groups: Cells with the same position within the boxes contain all the numbers 1 to 9.
• Friendly Cells: A blue cell contains its row, column or box number (in normal reading order). All possible friendly cells are given.
Solution code: row one
on 22. May 2026, 16:45 by TheCutmaster
Great puzzle! I found the term “box number” to be ambiguous; it could mean number within the box or number of the box within the puzzle as a whole.