The Gift of Life (Still Life Sudoku)
(Published on 16. August 2026, 14:10 by RightHandedNeutrino)
Still Life is a ruleset originally created by Sktx based on the Game of Life by John Conway.
Rules:
Normal sudoku rules apply
Place the digits 1 to 9 in each row, column, and 3x3 box.
Killer Cages
Digits in a Killer Cage sum to the small clue in the upper-left corner of the cage.
Still Life (negative constraint)
Shade some cells green ("live cells") such that the – up to – eight cells neighboring each green cell contain exactly 2 or 3 other green cells and the neighbors of each 'unshaded' – or grey – cell ("dead cells") do not contain exactly 3 green cells
– A CIRCLED cell's digit indicates the number of cells that are in the SAME state as its own in its neighborhood, INCLUDING its own cell
– A SQUARED cell's digit indicates the number of cells that are in a DIFFERENT state from its own in its neighborhood (therefore not including its own cell)
ALL CIRCLED AND SQUARED CELLS ARE GIVEN
Play the puzzle on Sudokupad
Solution code: The digits in the dead cells of row 9 (left to right) followed by the alive cells in column 9 (top to bottom)
Comments
on 27. August 2026, 19:01 by Kafkapharnaum
Saw you had another Still Life up so I figured it was more than time I came back to finish this one, and wow, that was some legit Killer logic to finish it off, not just some ordinary disambiguation! But the most impressive thing about this puzzle remains the implementation and role of the negative constraint, as even though it was mentioned in previous SL, in reality it never really played a role, so this is a first imo, well done!
And I see for your new puzzle that you went with just the pure ruleset, but I think combos with more classic variants is the way to go to reach a larger audience – in any case, you inspired me to take the ruleset up again and breathe some more life into this variant hehe
--------
This is indeed a killer disguised as a SL, thank you for the kind words! At this point I'm more interested in setting a cool/hard puzzle, but I will experiment more!
on 20. August 2026, 03:37 by Hellolol
Definite 5 star from me. Shading the last 2 columns was absolutely brutal, and I made so many mistakes that I had to backtrack from. also, finding the single digit that made the entire thing work after I had gotten all the shading done took me longer than I would like to admit. This was the first time i've done a still life puzzle, and wow! It was really good, I'll have to try more of them.
--------
Congratulations! I hope you liked the solve as much as I liked to set this puzzle!
Even knowing the solution it still took me like an hour to walk through all the deductions, so I wouldn't be surprised about it taking a quite some time to figure out
