Normal sudoku rules apply
Duplicated Quadruple: Each circle is surrounded by exactly the same four digits---to be determined by the solver.
Clones: The two grey regions are 'clones' of each other. They each have the same digits in the same positions.
Cages: Digits in a cage must sum to the number printed in its corner.
Little Killer:Digits along diagonals pointed to by arrows must sum to the given number. Digits may repeat along the diagonal if allowed by the other rules.
Solution code: row 5 followed by column 6 (no commas or spaces)
on 29. October 2021, 17:39 by uvo_mod
Labels ergänzt.
on 25. October 2021, 14:38 by ScatterBrain
Nice how the little killer clues were left with 1 degree of freedom for a while, and had to be worked a second time.
on 23. October 2021, 13:16 by Eloi.blok
Nice puzzle, tks!