This week's featured Hanayama puzzle is the Cast Coil, designed by Edi Nagata and released early last year. The coil is actually an updated version of the 29th IPP entrant Twin Snake, which was built from Movingui wood and had a couple of different challenges, besides simply taking it apart. The key word for this one is "loops".

The Coil is comprised of two seemingly identical pieces coiled up and entangled, which at first glance look like four linked pieces. The concept reminds me of Richard Gain's Superstrings, but in a more compact structure. The idea is to take the two pieces apart and then, of course, find a way to coil them up again.

The two pieces have each their own color, which gives this stunning alternating pattern of silver and gold. It looks like it's made of brass, at least judging by the smell it leaves on your hands and the smoothness of the surface. I was surprised by how small this one is, compared to other Cast puzzles: it measures only 3.3cm in height and 2.5cm in length (that's about 1.3" x 1").

(Click to Enlarge) - Left: Alternate View; Right: Partially Disassembled

Difficulty-wise, the Coil is not that hard. Hanayama rates it as a level 3 out of 6, and unless you're really unlucky, you should be able to solve it within 10 minutes or so. The solution is not exactly as straightforward as you'd expect it, but once you get the hang of it on how the pieces maneuver, it becomes clearer. Some of the moves you'll be doing involve sliding and rotating, and even though it moves counter-intuitively due to its angular shape, there are a few strategically placed circular cuts that will help you rotate the pieces in the desired way.

After you successfully separate the two pieces, you can easily check that while they appear similar at first, there's a slight difference between them, as the silver piece has an extra circular cut in it. As with most disentanglement puzzles, you'd expect it to be harder to put together than to take it apart, because it requires a deeper knowledge of how the pieces interact with each other and ultimately, a complete understanding of the solution - not just utter luck. However, I found it to be way easier to reassemble it. It took probably 2 or 3 minutes to put the pieces back together. Was it just pure luck? - I'm not sure, but I won't find out anytime soon. I'll leave it as it is, for now...

Closing Comments:

The Cast Coil turned out to be a little different from its wooden predecessor, but that's not necessarily a bad thing. The wooden version had an engraved symbol of the puzzle on it and you had to successfully recreate it when you were reassembling it. It had this extra challenge and I liked it its originality. Unfortunately, the metal version doesn't have this feature, but it's understandable, because it's very difficult to engrave something on a piece of metal this size. The end result is still a great puzzle and I highly recommend it - It's a Hanayama puzzle after all, and you can't go wrong with that...

Availability: You can get a copy of the Cast Coil at Sloyd.fi, as well as all the others in the Cast Puzzle Series.

Links:

Hanayama Cast (in English) - Very useful website in English, with plenty of information on all things Cast.

Hanayama's Factory Visit (Many thanks to Roxanne Wong for sharing these pictures)