(This post is part of the Genuinely Approachable Sudoku (GAS) series.)
Philip’s wife: 🎵 Math-y birthday Sudoku! Math-y birthday Sudoku! 🎵 This X-Sums Sudoku quite literally has Philip’s numbers written all over it. Happy 44th, love!

PDF

or solve online (using SudokuPad)

Theme: Birthday Maths

Author/Opus: This is the 140th 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, the clues outside the grid indicate the sum of the first X numbers placed in the corresponding direction, where X is equal to the first number placed in that direction (e.g., if R9C2 is 5, then the five numbers in R9C2, R8C2, and on to R5C2 all add up to 26).

GAS Time Standards (highlight to view): Two party hats (🎩🥳): 7:29; One party hat (🥳): 44:44. All other solvers earn an 🦕: English Europatitan.

Thomas Hits the GAS (highlight to view): 3:25, 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.