Following Philip’s last “Irregular” Sudoku, this puzzle requires having an even and odd number on opposite sides of each bold boundary, making a more challenging variation until you plan for the disparities.

PDF

or solve online (using our beta test of Penpa-Edit tools)

Author/Opus: This is the 23rd 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. Across the bold region boundaries, the numbers must be of opposite parity (i.e., even on one side and odd on the other). For example in this puzzle: if R1C6 is odd, R1C7 must be even. If R1C6 is even, R1C7 must be odd.

GAS Time Standards (highlight to view): Two party hats (🎩🥳): 8:30; One party hat (🥳): 18:00. All other solvers earn a 🦕: August Aepysaurus.

Thomas Hits the GAS (highlight to view): 5:08, 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 classic Sudoku. If you are new to this puzzle type, here are our easiest Sudoku to get started on. More Sudoku including variations can be found in these books in our e-store. Also, visit this page to purchase all of the puzzles from the 16th World Sudoku Championship including classic 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.