159 RSL
- Region sum lines
The brief
Normal sudoku rules apply.
159: Digits in column 1 indicate the column in which the digit 1 appears in that row (e.g. if r4c1 is a 6, r4c6 is a 1). The same applies to columns 5 and 9, with the digits 5 and 9 respectively.
Region Sum Lines: Digits along a blue line have an equal sum N within each box it passes through. Different lines may have different values for N.