At 21 feet, 9 ¾ inches long, and with 8,929 empty squares to fill, this huge puzzle adds big excitement to the popular game. It’s composed of 167 regular-sized (9x9) puzzles, linked together at 3x3 corners. Each individual sudoku’s starting numbers are symmetrically placed, and no more than 30 numbers are given. Also, each 9x9 puzzle has a unique solution—and the difficulty level increases as you progress from left to right for a formidable sudoku!