Kuromasu by Thomas Snyder
or solve online (using our beta test of Penpa-Edit tools; use tab to shift between shading mode and the linex mode where left click+drag draws lines and right click marks X’s)
Theme: Clue Symmetry and Logic
Author/Opus: This is the 191th puzzle from Thomas Snyder, aka Dr. Sudoku.
Rules: Shade some empty cells black so that each number indicates the total count of white cells connected vertically and horizontally to that number including the numbered cell itself. Black cells cannot share an edge, and all white cells must belong to a single connected group. Or see this example:
Answer String: Enter the length in cells of each of the white segments from left to right for the marked rows, starting at the top. Separate each row’s entry with a comma. This example has the key “14,221”.
Time Standards (highlight to view): Grandmaster = 2:00, Master = 3:30, Expert = 7:00
Solution: PDF
Note: Kuromasu is a new puzzle for us this week and we are curious to hear what you think of it.
01:50. Better!
Nice puzzle. Feels easier than the Monday.
Interesting bit of logic with the center 7.
It must be a good puzzle, because I just solved it for the second time without realizing I had duplicated it the whole time (thinking it was today’s puzzle).
Aesthetically, these single kuromasu do have prettier solutions than the Caves.