Smashed Sums by Serkan Yürekli
or solve online (using our beta test of Penpa-Edit tools; use tab to shift between number entry and shading modes.)
Theme: Order and Disorder
Author/Opus: This is the 375th puzzle from our managing editor Serkan Yürekli.
Rules: Fill each row and column of the grid with the digits 1 to 5 and two blackened cells. Numbers outside the grid indicate the sum of the digits between the two blackened cells in that row or column. Blackened cells are allowed to touch. Or see here.
Difficulty: 3 stars
Time Standards (highlight to view): Grandmaster = 4:30, Master = 6:30, Expert = 13:00
Solution: PDF and solving video.
Note: Follow this link for other less common Number Placement puzzles.
Didn’t find the breakthrough point, just “looked-ahead” till I hit a dead end after the first 10 deductions, and I actually solved everything in 1 go.