Sunday 22 April 2012

Cast Nutcase

Hanayama Cast Nutcase
I really do apologise for the delay since my last blog post! Work seems to get in the way of the more important things in life like puzzles sometimes. I will try my hardest not to let it happen again. This time I am going to review the Cast Nutcase from the Hanayama puzzle company. This one came from Puzzle Master where it is a very reasonable $17. It was designed by the amazing Oskar van Deventer.

It comes well packaged in the usual Hanayama black box - It is a rather nice galvanised bolt with two nuts on it. So why is it called a nut case? Because if you shake it you can hear it rattle and when you look for the source of the noise you can see that there is a cavity in this puzzle containing a small nut! The puzzle is 5cm tall and 3.4cm in diameter - it looks and feels really quite substantial. It has been reviewed before by my fellow puzzle bloggers - Neil, Brian and Jerry.

Puzzle Master have rated it as 10 out of 10 (Mind Boggling) in difficulty and this matches Hanayama's own rating of 6 out of 6. I have to say that I think the comprehension of this puzzle is much easier than that (maybe 8 out of 10) but the execution is considerably tougher. The fact that the other reviewers have stated that they completed this one in an hour or less does mean that this is not as tough as some of the other top level puzzles which may have taken many hours to solve. As with all the Hanayama puzzles - no solution is provided. If you find you want one then it can be downloaded from Puzzle Master here.

The initial challenge with this one is to open the case and release the small nut from the case and then put it back together again. After only about 4 or 5 minutes of fiddling with this one it became quite clear to me what the mechanism had to be. Unfortunately actually carrying out the procedure that I knew had to be the solution was really considerably tougher - I think it took me about 45 minutes to open it. Because of this it feels like quite an achievement when you do manage it. I am not a lock picker but I can imagine that the technique used to solve this is rather similar - you know how it works, but it requires a lot of trial and error and feeling small changes occur inside as you work it out. My only real criticism was that the nuts on the outside do not turn as smoothly as I would like and sometimes seem to  get cross-threaded. This really interferes with the opening mechanism because you do have to be absolutely precise in your actions.

The nut has been released from its case
There is also a secondary challenge with this one - the next challenge is to put the nut back into the case with the external nuts the other way around so that it reads CASE NUT instead. Neil stated that he felt this takes the difficulty level up to 11! I am not sure I agree with him - it is a bit tougher than the original but unlike Spinal Tap, I don't think it turns it up to 11! This took me an extra 20 minutes.

Now it's a Casenut!!
Can I recommend this puzzle? It is not as pretty as some of the other Hanayama puzzles but still worth owning and solving. I do think it is a clever idea and is a reasonable challenge. I have handed it to quite a number of friends now and most have worked out the principle behind it and managed to tell me what is required but NONE of them have actually managed to physically solve it. I think my main "victim" has come fairly close but with this one that doesn't cut it!! If you are a collector then it should be part of your collection.


  1. Absolutely hate it. It could be so much better but the manufacture of it severely lets it down. I managed to cross thread mine initially quite badly and it took quite a bit of messing about before I managed to release it properly. It could be a cracking puzzle if they paid a little more attention to detail.

  2. I got this puzzle when it first came out (several years ago). I did not know any "safe cracking techniques" and tried a systematic approach. This ended in failure and I couldn't understand why. I was forced into safe cracker mode and since I didn't know what this was I cut off thin strips of paper and poked them under the threads. I eventually solved it but was not too happy to have used "external aids". Now I am a more experienced safe cracker and know more what to do.

  3. If I'm not wrong, the first version of this puzzle was not only sturdier (bigger in dimension), but also more difficult to solve due to a "non-systemic" position of the nuts. The smaller version has
    a "systemic" position of the nuts.

    1. I'll have to take your word for that! I was not aware of that at all!

  4. I think it is a good work by Oskar van Deventer. Difficult but amazing.

    1. This is ok but certainly not one of the best Hanayama puzzles.