About this puzzle
Sudoku - also known as "Number Place" - is a logic-based, combinatorial number-placement puzzle. The aim of Sudoku is to enter a number from 1 through 9 in each cell of a grid, most frequently a 9×9 grid made up of 3×3 subgrids. Each row, column and region must contain only one instance of each number.
This Sudoku variant is called "Windoku", "Four-Box Sudoku" or "Hyper Sudoku". The puzzle contains four additional 3×3 regions that must contain the numbers 1 through 9.