The Key puzzle (Level 1) is one of the longest-selling Hanayama Cast Puzzles. Key II is a more sophisticated version of that puzzle, emphasizing style and precision. The objective is to separate the two keys and then restore them to their initial state. It looks simple, but in fact involves a little trick. Beginners should therefore be careful not to pull them apart by force. Designed by Otake & Wong, Key II has a difficulty level of 2 (fairly easy).