No pencil nor paper required. Made of beech wood, 81 thinking tiles. The best way to train brain. 2 spare tiles per number included. Comes with a booklet of 100 sudoku puzzles. Two spare tiles per number (in a bag) all fit neatly into the drawer; Each tile is double-sided, black for numbers youre sure about, red for possibles. The objective is to fill a 9×9 grid with digits so that each column, each row, and each of the nine 3×3 subgrids that compose the grid (also called boxes, blocks, regions, or subsquares) contains all of the digits from 1 to 9. Makes a great board game gift for number-puzzle lovers.