The Big Book of Logic Puzzles - Triple Doku 400 Hard (Volume 3)

Sudoku (also known as "Number Place") is a logic-based, combinatorial number-placement puzzle. The objective is to fill a 9x9 grid with digits so that each column, each row, and each of the nine 3x3 sub-grids that compose the grid (also called "boxes", "blocks", or "regions") contains all of the digits from 1 to 9. The puzzle setter provides a partially completed grid, which for a well-posed puzzle has a single solution. Triple Doku - 3 sudoku puzzles that has overlapping areas. All grids must solved according to sudoku rules.