or solve online (using our beta test of Penpa-Edit tools; use tab to shift between number entry and shading modes.)
Theme: 1 to 10
Author/Opus: This is the 372nd puzzle from our managing editor Serkan Yürekli.
Rules: Fill some cells with numbers 1-4 so that each row and column contains each number from 1 to 4 exactly once as well as two empty cells. Numbers outside of the grid indicate the sum of all numbers in the first connected group in that direction as in a Japanese Sums puzzle.
Difficulty: 2.5 stars
Time Standards (highlight to view): Grandmaster = 2:00, Master = 3:15, Expert = 6:30
Note: Follow this link for other Japanese Sums puzzles.