Factor Lines Sudoku by Philip Newman
(This post is part of the Genuinely Approachable Sudoku (GAS) series.)
Each line in this intriguing puzzle is connecting pairs of factors, so thinking of what numbers can come together and which cannot is essential throughout most of the solve.
or solve online (using SudokuPad);
[update 2025-08-29-10:00 AM PT] see also the author’s “fixed” version in SudokuPad which adds a given but is similar in difficulty. This version did not survive typesetting so we never saw it until after our own publication here. There have been a lot of asymmetric puzzles this month and we don’t directly edit the GAS except to confirm valid puzzles and reasonable times; we’ll discuss together if / how we do patches in the future if GAS make changes after our publishing.
Theme: The Cold, Hard Factors
Author/Opus: This is the 31st puzzle from Philip Newman, part of the Genuinely Approachable Sudoku (GAS) team.
Rules: Standard Sudoku rules (insert a number from 1 to 9 into each cell so that no number repeats in any row, column, or bold region). For every pair of adjacent values connected by a line, one number is a multiple or a factor of the other. It is possible for a number to be adjacent to itself on a line. (For example if R3C4 were 3, then R2C3 which is connected to R3C4 could be 1, 3, 6, or 9, because 1 is a factor of 3, 3 is a factor and multiple of itself, and 6 and 9 are multiples of 3.)
The color of the lines in this puzzle is for artistic purposes only.
GAS Time Standards (highlight to view): Two party hats (🎩🥳): 8:00; One party hat (🥳): 24:00. All other solvers earn a 🦕: August Austroposeidon.
Thomas Hits the GAS (highlight to view): 3:27, with SudokuPad replay file shared as a download for now (requires loading via settings menu with improvements expected before people should use this regularly).
Solution: PDF; solving video with explanation to be added later from GAS team.
Note: Follow this link for other less common variations of Sudoku.
Note 2: Comments on the blog are great! For a more interactive discussion, please also consider using our Daily GAS discussion post on the GMPuzzles Discord. Not a member of the Discord? Click this link for basic access.