1) Normal Sudoku rules apply
2) Region Sum Lines: box borders divide blue lines into segments that have the same sum. This sum may be different for different lines. In this puzzle, blue lines do not share cells, branch, or cross themselves or each other
3) Dynamic Fog: Entering correct digits will clear fog from that cell, and may clear fog from other cells
You can play it here: SudokuPad.
Solution code: Row 9
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