Kumiki is a Japanese word that means "to join wood together." Japanese artisans have crafted Kumiki wooden puzzles for over 100 years. Tradition says the puzzles are based on the earthquake-proof technology of locking wood components of buildings together without the use of nails. Solving these puzzles usually involves the final placement of a key piece or pieces with either a shove or a twist to lock them in place. A set of twelve of the wooden stumpers came with individual instructions for solving each puzzle. This was marketed around 1955.