Sudoku Challenges

Sudoku Challenge is a logic-based combinatorial number-placement puzzle. The goal is to fill a 9 × 9 grid with numbers such that each column, each row, and each of the nine 3 × 3 subgrids (also called “boxes” or “blocks”) that make up the grid contain all the numbers 1 through 9. Each puzzle will start from a partially completed mesh that has only one solution.