Endless fun for devoted solvers! At 21 feet, 9 3⁄4 inches long, and with 8,929 empty squares to fill, this huge puzzle adds big excitement to the popular game--and is the perfect challenge for fans who find regular sudoku too easy. It's composed of 167 regular-sized (9x9) puzzles, linked together at 3x3 corners. Each individual sudoku's starting numbers are symmetrically placed in the puzzle, and no more than 30 numbers are given. Also, each 9x9 puzzle has a unique solution. And, finally, the difficulty level increases as you progress from left to right, becoming quite formidable by the end.