I received the HanayamaCast CoilfromPuzzle Masterin Canada. This one is one of the newest in the Cast series. It is rated as Level 7 out of 10 (Challenging) by Puzzlemaster and on Hanayama's own scale up to 6 it is rated as a 3. I personally agree with this rating. In all it took me about an hour to solve this and understand it (it could have been quicker but I got stuck having missed a move).
Just as with the others it is very well packaged with rudimentary instructions on the box and no solution is given (if you need one then find ithere). This is a fairly small cube measuring 34x33x25mm but despite the size it is a surprisingly heavy weight. It consists of two pieces of metal folded into identical convoluted shapes (identical apart from a few little cut-outs) which are wound around each other to form the cube. It looks quite attractive but my only disappointment with it is that the finish is pretty tarnished to mimic an aged look - I would have preferred the lovely shiny look of the Cast Key II or Keyring. The aim, obviously, is to separate the two pieces and then put them back together again.
2 almost identical pieces
This one is significantly harder than the last two - it is not horrendous but there are quite a few more choices to be made and dead ends along the way. The moves require a series of linear translations and rotations (because of this the puzzle is not solvable using a program like Burrtools). There are multiple choices of movements that can be made at a number of places. I made an error after the second move and got completely fixated at this point for quite a while. Only after giving up for an hour and coming back to it did I discover the correct 3rd move and had only a small amount of trouble with the 4th move. After this it was relatively straight-forward reach the end point, although you don't realise you are at the end point until they slide apart. Putting it back together was a breeze because I had drawn a decision tree. All in all this one took me a total of about 20 minutes to solve - very enjoyable. I let my long-suffering wife loose on this one because she actually admired the look of it and for once expressed an interest in trying a puzzle. She gave up without realising she was one step away from the solution! However she had such a completely chaotic approach to solving it that there would have been no chance of a reassembly. Several friends have watched me playing with this like a worry bead (it is quite therapeutic!!) and without fail all have reached for it to have a quick fiddle. Surprisingly they all failed to solve it! I suspect that proper time and concentration is the only reason they failed. Only one of my friends, whom I have tortured the most has managed it. I really enjoyed this one - it is a more significant challenge than the previous ones and looks great.