(This post is part of the Genuinely Approachable Sudoku (GAS) series.)
Today’s puzzle is something of a twist on the Kropki Pairs variant common in GAS puzzles, but with a negative constraint: there is nowhere to place a white (consecutive) dot in the grid!

PDF

or solve online (using SudokuPad)

Theme: Partial Pairs

Author/Opus: This is the 101st 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). No two orthogonally adjacent cells can be consecutive (i.e., differ by 1). Also, if a black circle is given between two adjacent cells, then the two numbers must have a ratio of 2. Pairs of cells without circles can have any relationship. (The numbers 1 and 2 can be adjacent if and only if there is a black circle between them.)

GAS Time Standards (highlight to view): Two party hats (🎩🥳): 6:00; One party hat (🥳): 12:00. All other solvers earn a 🦕: Rhombidodecadodecahedronic Rhomaleopakhus.

Thomas Hits the GAS (highlight to view): 2:33, 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.