Wednesday 15 June 2011

Hanayama Cast Rattle

Cast Rattle

My recent batch of puzzles from Puzzle Master included the Hanayama Cast Rattle, one of the most recent from the very prolific puzzle producing company. This puzzle was designed by Bram Cohen and is rated as 8 out of 10 (Demanding) by Puzzle Master and 4 (out of 6) by Hanayama. I therefore expected this to be a fairly significant challenge this time.

As usual, it is well packaged and the instructions just say to separate the four pieces which make it up. No solution is provided and I think that one is not really needed - most people should be able to work this out eventually. If you do want a solution then you can download one from here. It consists of four pieces each identically shaped that are loosely interlocked together (dimensions when assembled are 40x38x26mm). Being so loose they all can shake about freely (but not fall apart) hence the name - Rattle. The pieces are made from a really lovely shiny chromed metal and the puzzle is fairly substantial weight. It does look at first glance that these should just unlock from each other pretty easily - BUT looks can be deceiving.

I started fiddling with this with the initial idea that I had to find a set sequence of moves to unlock it. It is actually quite awkward to investigate it properly because all the pieces move around so freely that it is very hard to hold things where you want them to be! Initially you just move pieces to and fro, locking bits into various slots that open and close. Over a little time you get a much more complete picture of the shapes of all the pieces - this, because of the very free movement, allows a complete view of all parts (albeit only in short segments). It soon becomes apparent that it is not going to come apart using this technique and once you know the full shape the important thing is to stop and.....


Once I had worked out in my head what was needed, then it still proved awkward to actually do it because the free movement of all the pieces works against you to get everything arranged the way you want them. It is important to have somewhere nice and flat to solve the puzzle on. My initial attempt was whilst watching TV on a sofa with a cat on my lap. First this pisses off your wife (jingling issues) and second it pisses off the sharp clawed cat (ouch!!!) and third it makes actually solving it even harder!!! Finally I got to a desk and was able to get the positions just right and the movement correct and it quickly separated into the 4 parts:

Cast rattle in pieces
I have shown only the picture of the parts which will not spoil the solution for you. All in all, it took me about an hour to solve this one. Putting it back together is a fairly trivial thing once you have solved it.

Overall this is a really clever puzzle and quite different from all the previous maze type puzzles I have tried from the Hanayama collection. It looks great on the shelf and irresistibly tactile. Definitely a good one to buy and to hand to friends - they are unlikely to manage to solve this one unless you give them a fair amount of time with it.


  1. I don't share your opinion that you need to do it on a table. I actually do it "in the air". However, I wipe teh puzzle clean and dry, and I wash my hands well and dry them well before solving it.

    Needed to say, this one didn't take so much time to me. After I realized that the solution is not "rattly", I used my math background and proved in my head that there is only one way how the solution can look like. Et voilà! In not more than 1 minute after, it all fell from my hands and ringed on the floor, disassembled.

    I love this one a lot, I handed it to couple people, and I need to say, girls seems to be better in this one than boys :)

    1. I found I needed to hold it still and arrange the pieces very carefully!