The Nutcase is designed by Oskar Van Deventer and made by Hanayama. As I found to my surprise it was actually very much larger than your regular household nut and bolt. It measures 2 inches tall and about 1 1/4 inch across at its widest. The puzzle looks like a "fat" screw bolt with two heads, one at each end and in the middle you have the two nuts. The puzzle is made of aluminium and while quality is not first rate, it is reasonably good. The screw bolt is actually hollow inside. Both ends of the puzzle each have a hole into which you can see a real small nut rolling about inside the hollow section.
|Can you see the lines which separates the two parts of the screw bolt?|
I fiddled with the puzzle for a while, rotating the two nuts back and forth along the axis of the screw bolt and managed to solve the puzzle after about 45 minutes. The free play of the two nuts and the screw bolt helped a lot as it allowed me to pull, push and twist the screw bolt while fingering the two nuts so I could feel for the separation of the screw bolt. The "looseness" of the nuts (and with the help of a torch light) also enabled me to peep a bit "inside" the nuts and their position relative to the threads of the screw bolt (I don't think Oskar intended this) and this got me to solving the puzzle very quickly :-). However, this looseness resulted in jamming of the nuts against the screw threads more than several times which was a bit of an annoyance.
Overall the Nutcase is a challenging puzzle and rated level 6 by Hanayama which is very difficult. I guess the rating is probably about right. Difficult to solve at first but not too difficult to repeat.