Normal sudoku rules apply.
Digits along an arrow sum to the digit in that arrow's circle.
A digit in a circled cell indicates how many circled cells contain that digit (arrow circles are also circled cells).
Digits separated by a black dot have a 1:2 ratio (i.e. one is double the other).
Digits separated by a king's move must be different.
Solution code: Row 5
on 10. July 2024, 14:05 by Fool on Hill
I found this clever and tightly constructed (and I learned some things about the king's move constraint that I may not have known before, or may simply have forgotten). It was tough too, but a great challenge for a fan of hard puzzles.