Sunday 6 November 2011

Hanayama Cast Donuts

Cast Donuts
This lovely little puzzle came to me courtesy of Wil Strijbos. Whilst on his travels after the Berlin IPP, he had managed to obtain a supply of the latest Hanayama cast puzzle. This one is only available in Japan at the moment and if you want one ahead of the international launch then you will need to contact Wil (email me for his details). It has already been beautifully reviewed by Oli on his blog here.

Like my last Hanayama review (the Cast Loop) it was designed by Vesa Timonen, a hugely talented designer who has turned his hand to many other types of puzzle including Lox in Box and quite a few burr puzzles. It arrives in the standard, top quality Hanayama packaging, although being entirely in Japanese I cannot tell you what the instructions are! I have to assume that the aim is to disassemble and then reassemble it! It consists of 2 donuts (surprise!!!) of shiny chromed metal which are interlocked through their central holes. One is a standard chrome and the other is a blackened chrome (similar to the Cast Quartet). Like most of this type of Hanayama puzzle it is extremely attractive and very tactile. Hanayama has graded it a 4 out of 6.

Initially it looks completely impossible - how do you disentangle two complete rings? But on closer inspection it becomes clear that the donuts are each made of 2 pieces - the shiny ones are complete rings and the darker ones are a more complex U shape. There is almost no movement in the puzzle - the two donuts will spin within each other but the parts of each donut will barely move.

You quite quickly suss out what is holding the pieces together but deciding how to separate them is a much more difficult task. The initial idea is to pull the pieces of the black donut apart and I think some people may have solved it in this way. My suggestion - DON'T do it like that! I suspect that it might be possible but may well require force. I have not solved it this way - my initial attempts were along those lines and I nearly got it stuck. A number of others have expressed dissatisfaction with the puzzle because the solution they found was not particularly elegant or required some force. The actual solution is far more elegant than that!

You do need to pull the pieces apart a little but only as part of your initial exploration to establish what the shapes are and how the pieces work. Once you have done this it is a "simple" matter of establishing the correct movement to allow all the parts to separate. Oli claimed this was almost as beautiful a solution as his favourite, the Cast Marble and I would agree. I do not own the Marble but have solved a friends' and it is lovely. This one is pretty close as an elegant solution.

You end up with 4 pieces which can be assembled into 2 separate donuts - hmm getting hungry now!

On one of Oli's comment threads it has been mentioned that there is an alternative reassembly - I cannot for the life of me see how that is possible! I wait with baited breath to see whether Oli finds it! If anyone knows of the alternative assembly then contact me here.

When it arrives in Europe then be sure to add it to your collections! In the North America it is already available from Puzzle Master here.


  1. Nice review! What a great puzzle! I've still had no luck with any alternate assembly. I can't see how one would be possible either.

  2. Bless the people at Hanayama. I LOVE their puzzles!