or solve online (using our beta test of Penpa-Edit tools; use tab to shift between number entry and shading modes.)
Theme: Multiples of 3
Author/Opus: This is the 27th puzzle from our contributing puzzlemaster JinHoo Ahn.
Rules: Place the digits 1-7 (1-9 for the example) in some of the cells, so that no digit is repeated in any row or column. Numbers on the outside of the grid indicate the sums of adjacent digit groups in that row or column, in order. Each sum is separated by at least one unused cell.
Difficulty: 3.5 stars
Time Standards (highlight to view): Grandmaster = 4:00, Master = 8:45, Expert = 17:30
Note: Follow this link for other Japanese Sums puzzles.