The normal Sudoku rules apply: in each row, each column, and each bold-outlined 3x3 box, the digits 1–9 must each appear exactly once.
Additionally:
Green spectral lines: Adjacent digits along any green spectral line differ by at least 5.
Blue spectral line: The digits on the blue spectral line sum to the atomic number of strontium in the periodic table of elements (for non-chemists: strontium has atomic number 38).
Yellow atoms: Around an atom, all surrounding digits are either all even or all odd. All atoms are given.
Red atomic nuclei: Around a red atomic nucleus there are always two pairs of identical digits in a cross formation (e.g., 2 2 and 4 4).
Electrons: Cells connected by a white electron contain consecutive digits. Cells connected by a black electron have a 1:2 ratio. Not all white and black electrons are given.
F-Puzzles-Link: F-Puzzles link
Solution code: The right column
yesterday, 14:46 by Rjw78
Thank you nagesh for the sudoku pad link
on 9. June 2026, 10:00 by VitP
there's an actual MISTAKE here (not just a rules ERROR).
first of all, we have to recognize that an ATOM and a NUCLEUS are NOT the same thing. not in chemistry, and not in this ruleset.
but what are we to do with the left nucleus ? it breaks the atomic negative constraint. on the other hand, the right nucleus does not.
also, this appears to be a grid-wide parity colouring puzzle with a negative constraint, and more. unlikely to be level 2.
on 7. June 2026, 22:17 by Zinker
Link added
on 7. June 2026, 20:15 by Nagesh
https://sudokupad.app/u7y38zz32n
on 7. June 2026, 13:52 by Harold
Puzzle link is missing
| Difficulty: | ![]() |
| Rating: | N/A |
| Solved: | 6 times |
| Observed: | 0 times |
| ID: | 000T6L |