(This post is part of the Genuinely Approachable Sudoku (GAS) series.)
Philip’s 1-8 diagonal pattern shows up again today, now with a challenging set of Region Sum Lines to figure out to complete the rest of the grid.

PDF

or solve online (using SudokuPad)

Theme: Professor Calculus

Author/Opus: This is the 45th 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). Along each line, the numbers in every region it passes through have the same sum. (In this puzzle, for example, R1C2 + R2C2 + R3C2 = R4C2 + R4C1 + R5C1 + R6C1 + R6C2.)

GAS Time Standards (highlight to view): Two party hats (🎩🥳): 8:00; One party hat (🥳): 20:00. All other solvers earn a 🦕: Yung Yunmenglong.

Thomas Hits the GAS (highlight to view): 3:39, 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 and solving video with explanation 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.