This famous mathematical wooden brain teaser puzzle used for math problem solving companies management tests. The 9 Rings version requires 511 moves to solve it. It is 4 times as difficult as the 7 ring version All the pieces can be stored inside the box for safe keeping. Starting with all 9 discs placed on the central stand. The goal is to transfer all the discs to the other stand in their original order. You may move just one disc at a time, and a larger piece can't be placed over a smaller one.