The River
by Jakhob and wooferzfg

Normal Irregular Sudoku rules apply, but the regions must be determined by the solver. All regions are orthogonally connected groups of 9 cells.

The blue line is a region sum line. Digits on the line have an equal sum N within each region it passes through. If the line passes through the same region more than once, each individual segment of the line within that region sums to N separately.

Puzzle Links

Play on SudokuPad

Play on f-puzzles