Normal sudoku rules apply. The white dot separates digits with consecutive values. Cells in the same position in two 3x3 boxes may not contain the same digit. (So eg, r1c1 and r4c4 cannot contain the same digit as these are both in the top left corner of their 3x3 boxes.) 'XYZ' means 'Row X Col Y is digit Z.' If XYZ is true, YZX is also true.