Normal sudoku rules apply. Digits on a line must have values strictly between those of the digits in both connected circles. Shade some cells such that all shaded cells are orthogonally connected and all unshaded cells are orthogonally connected. No 2x2 area may be fully shaded or fully unshaded. The circles act as "minesweeper" clues. Cells containing a circle are always unshaded, and their value is the number of shaded cells in the surrounding 3x3 area (i.e. the up to eight cells that touch the circle either orthogonally or diagonally).