Rules of the game Sudoku Kropki 9x9 #10 online for free
You need to fill in the gaps in the following way so that all rows, all columns, as well as any 3x3 blocks can contain numbers 1-9 in exactly one occurrence.
A white circle between the two boxes indicates that one of the two numbers in the two boxes must be 1 more than the other exactly.
A black circle between the two fields indicates that one of the two numbers must be exactly the other twice.
Between two fields is not a loop, neither of these rules can be applied.