The hidden secret of this Padlock pocket puzzle is loosely guarded. The four pieces are easy to wiggle and rotate but not so easy to get apart. Normally, Hanayama cast puzzles are carefully engineered to create a precision fit. Perhaps the unusual nature of this puzzle’s design is a clue to the mechanism? If you do manage to fiddle the Padlock pieces apart, you may be surprised at how stubbornly the puzzle refuses to fit back together again. JinHoo Ahn won Honorable Mention in the Nob Yoshigahara Puzzle Competition in 2014 for this design. Produced by Hanayama of Japan.