(This post is part of the Genuinely Approachable Sudoku (GAS) series.)
While the grid may look “classic” to you, you’ll need to know that no pairs sum up to 5 or 10 to make progress.

PDF

or solve online (using SudokuPad)

Theme: Two Deadly Givens

Author/Opus: This is the 18th 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 numbers in adjacent cells can sum to exactly 10 or 5 as in the Roman Numerals for X or V. (This is the same rule as in XV Sudoku, but there are no X or V clues given here so it is Anti- only.)

GAS Time Standards (highlight to view): Two party hats (🎩🥳): 8:00; One party hat (🥳): 16:00. All other solvers earn a 🦕: Silent Seismosaurus.

Thomas Hits the GAS (highlight to view): 3:20, 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.