Sudoku Fobidoshi - 200 Hard to Master Puzzles 8x8 (Volume 4)

(" ") is a logic puzzle, invented by Naoki Inaba (Japan). It is played on a rectangular or square grid. Some of the cells have circles in them. The aim is to place circles into empty cells; all the circles must form an orthogonally continuous area. A line of connected circles must not contain more than 3 circles.