PDF

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 42nd puzzle from our contributing puzzlemaster Prasanna Seshadri.

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 = 5:15, Master = 8:00, Expert = 16:00

Solution: PDF; a solution video is available here.

Note: Kuromasu is a new puzzle for us this week and we are curious to hear what you think of it.

• John B says:

Analyzing the group of threes was interesting, and in general the abundance of odd numbers set up parity considerations. Breakin was harder to find than it should have been. I liked the use of the upper right 4. Good use of blacks, good conclusion, and for some reason this just has a Prasanna feel to it that might make it easier to guess the author if anonymous.

• chaotic_iak says:

03:50. Why am I so quick at this ._.

The “lemma” of “2 near the corner” helps a lot in this puzzle. Have a bit of intuitive feeling here, but very well done.

• skynet says:

17:16

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