(This post is part of the Genuinely Approachable Sudoku (GAS) series.)
Philip returns with this familiar pattern, and a very difficult set of placements with only a few parity clues shared in the form of even squares and odd circles to break through.

PDF

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

Theme: I Won’t Back Down

Author/Opus: This is the 39th 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). Also, cells with a square contain an even number; cells with a circle contain an odd number.

GAS Time Standards (highlight to view): Two party hats (🎩🥳): 10:00; One party hat (🥳): 25:00. All other solvers earn a 🦕: Partitioned Protognathus.

Thomas Hits the GAS (highlight to view): 6:07, 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 more Even/Odd Sudoku puzzles. If you are new to this puzzle type, here are our easiest Even/Odd Sudoku to get started on. More Even/Odd Sudoku can be found in these books in our e-store.

Note 2: Comments on the blog are great! For a more interactive discussion, please also consider using our week-0-discussion thread on the GMPuzzles Discord. If you are not yet part of this Discord community, use this link. Not a member of the Discord? Click this link for basic access.