Cast Helix

Cast Helix

Taking a small break from the Puzzle Master wire puzzles, I decided to go back to one of the Hanayama puzzles. This time it's the Cast Helix. I thought I should work out how to solve this one because a friend of mine at work had been attracted to the shiny metal puzzles as a direct result if playing with some that I had brought in. She had bought the Cast Marble which she has so far dismantled but not reassembled and also bought the Cast Helix. She has spent weeks on this one and gotten nowhere and I knew that I couldn't help her if she asked. So it was time for me to work on it.

The usual black Hanayama box beautifully displays this puzzle. It consists of 2 disks of antiqued brass attached back to back with multiple slots in each. A robust metal helical piece passes through both disks. Size is 4.3 x 6.2 x 6.2 cm with a nice solid feel to it. The helix can be rotated around the disks through the holes that appear as you rotate the 2 disks in each other and can get to more or less any position you might want. The disks have a number of shapes on the surface forming the shape of a logarithmic spiral and some gaps which move as the disks rotate. The aim is to remove the helix from the disks. There looks to be a fairly obvious exit point so what can be so tough that has kept her going for so long?

But remember it is a Puzzlemaster level 9 (Gruelling) or Hanayama level 5/6 so it is certainly not going to be trivial - it should be pretty tough. The reviews on the Puzzle Master page are generally good with the only negative that some force is required for the solution. This idea was confirmed in the review by Gabriel. No solution is provided but it can be downloaded from here.

The exit point looks fairly obvious just by looking at it. So having duly memorised where the starting point was so I could return it for the above photograph, I started to wend my way toward the intended spot. I got there reasonably quickly and then hit a little obstacle - I couldn't actually utilise the exit point. I knew a little force was required but to do what I wanted to go seemed to need a LOT of force. This couldn't be right! So I went back to the beginning and thought I'd sneak up on the exit from a different direction and catch it by surprise! Nope! Still no luck.

At this point I realised that I must need to do something special do utilise the exit. Now having read various on-line reviews I was aware of the sort of movement required just not how or where it should be done. I think I must have fiddled for an hour or two before suddenly I had a new configuration.

Caste Helix in pieces - some force required

From this new special position it is fairly awkward to remove the helix but it comes off with a little click. Returning it is not particularly tough as long as you noted the position of the exit. The force required is not high but if you expected it to just slide apart then you will never solve it.

Do I recommend it? For experienced puzzlers and collectors, yes absolutely! It is a nice interesting idea, totally unlike anything that has been seen before and at $13 it's a bargain. For people new to puzzling, I would not recommend it - it's quite counterintuitive and the small amount of force required may mean they never solve it. I suspect I'll have to help my friend. Hopefully she'll forgive me!!!

It does make a nice worry bead - I have been carrying it with me for a week now and find the moves quite therapeutic.