Kuromasu by Murat Can Tonta
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: Antisymmetric 2 & 3
Author/Opus: This is the 120th puzzle from our contributing puzzlemaster Murat Can Tonta.
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. Also 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 = 2:15, Master = 4:30, Expert = 9:00
Solution: PDF
Note: Follow this link for more Kuromasu puzzles.
Why is Kuromasu classified as “Region Division” puzzle?
Ontologies are never perfect, but in our view Kuromasu has a lot in common with Cave and other types in this category that are defining “in” and “out” groups. In this case the “out” are just single shaded cells, but you are trying to define a large region with intact pathways to get to a total size count.