Rules:
Normal Sudoku: Standard Sudoku rules apply.
Weiqi: For any black circle the sum of digits placed in adjoining cells is greater than 19 (2 by 2 cells), 9 (two border cells), or 4 (one corner cell), respectively. For any white circle, the sum of digits is smaller than 19, 9 or 4. All possible circles are given.
Solve In SudokuPad