Kuromasu (Double) 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: Three Times Four …
Author/Opus: This is the 7th puzzle from guest contributor Murat Can Tonta.
Rules: Shade some dominoes (pairs of 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. Dominoes 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 “23,15”.
Time Standards (highlight to view): Grandmaster = 2:45, 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.
02:06.
Impressive puzzle. It was pretty daunting with only eight clues, but turns out it wasn’t that difficult. Nice work.
I ended up doing this one by a bit of intuition, since the Double variant (and Kuromasu in general) are unfamiliar to me logic-wise. I think I started to get some ideas of how it works though.
I enjoy kuromasu in general, but this was particularly elegant.