Inventor Akio Yamamoto wrote, "In the summer of 1997, I saw two mackerels that had somehow managed to get into the sardine tank at the aquarium. Watching the two fish unable to blend in with the shoal of sardines made me wonder if they were on a journey of self-discovery. What sort of adventures will they have? Imagining this led to the conception of six cast puzzles based on oceanographic subjects." Hanayama is known worldwide for challenging puzzles and quality manufacturing. Can you take the pieces apart, then put them back together again? Hanayama cast metal brain teasers have 6 levels of difficulty, and each puzzle is Mensa-rated. Level 1 puzzles are considered easy by most puzzlers.