Product 9!
(Published on 2. February 2026, 19:57 by GraphZahl81)
Standard Sudoku rules apply: Place each digit 1-9 once in every row, column, and 3x3-box.
For all sets of nine cells at the same relative positions in their 3x3-boxes (e.g. the nine cells in the upper-left corner of their respective box), their entries have the same product.
Each of the seven lines in the puzzle (colours are used to distinguish them) is a palindrome line: The sequence of digits on it reads the same in both directions. All line segments between two cells are visible, i.e. no two lines directly connect the same pair of cells.
Finally: There exist two diagonally adjacent cells that both contain the digit 5.
Solution code: Digits of row 8 from left to right
Comments
on 3. February 2026, 07:41 by GraphZahl81
Approaches might differ a lot for this puzzle. The intended approach uses a minimal amount of note-taking and should solve it fairly quickly, thus the 2* rating.
The "all products are the same" condition implies that some digits have more constraints on where they can appear than others. If these constraints are observed consistently, one can get very far without the need to take any notes.
on 3. February 2026, 01:09 by dzamie
Most of this puzzle is in the note-taking, but boy is it still a puzzle. I wonder if I missed something that was supposed to be obvious, since 2* puzzles don't usually take me an hour and a half.
