You are about to access our book library "200 Kakuro and 200 Hitori sudoku. Very hard version: 17x17 + 18x18 + 19x19 + 20x20 Kakuro Sudoku and 17x17 + 18x18 + 19x19 + 20x20 Hitori sudoku ... sudoku puzzles. (Kakuro and Hitori puzzles) full version" .