You can get really far into this puzzle without relying on the negative constraint, perhaps just long enough to forget it’s there.
Rules:
Normal Sudoku rules apply.
Full Kropki: In cells separated by a white dot, the digits are consecutive. In cells separated by a black dot, one digit is double the other.
All dots are given, so cells not separated by a dot contain digits that are neither consecutive nor double the other. Remember this, it will help!
Estimated difficulty: 1 out of 5
Solve on SudokuPad