Sunday 23 October 2022

Hanayama Cast Cross

Hanayama Cast Cross - man, these things are tough to photograph!
Every now and then after a chat with my wonderful talented friend, Frederic Boucher, he decides that I don't have enough puzzles and he spontaneously sends me a lovely (not so) little care package containing a bunch of his new creations and others that are available only in Japan. Luckily he doesn't speak to Mrs S who has completely the opposite opinion and who would very much prefer it that I don't order any more. Luckily she who must be flinched from has spent the last week up in Edinburgh visiting the outlaws which allowed to me receive a new pair of toys as well as my bunch from Frederic without her seeing the sheer size of the packages. I hope that she doesn't get to review the Ring camera video footage and realise that I have been very baaad! Do I dare tell "her" about the new twisties I have recently ordered? Gulp!

Amongst the lovely package of toys from Frederic was the new Hanayama Cast Cross. I had fiddled with it idly at the last MPP and realised that despite the Hanayama 3/6 (PuzzleMaster 7/10) difficulty rating, this was not going to be one that I would solve really quickly and having realised that the movements needed to be very precise, I decided to wait until I had my own copy. I was delighted that Frederic saw fit to give me one (he's so so generous). 

Having unpacked my parcel and stashed them where Mrs S wouldn't notice (have I told you before that I haven't tidied my study in over 5 months?) and I set to playing with this one on Wednesday whilst attending a virtual conference (these are a wonderful new thing since Covid started - if you are a home-body like me then these are fab!) I idly fiddled with my new toy whilst watching a talk. I quickly realised that the two pieces of this puzzle are almost identical apart from one key feature. This is effectively a disentanglement puzzle using chunky metal instead of wire. It is rather satisfying to play with. The first move is nice and linear giving me the expectation that all moves would be using the rectilinear grid, including rotations to get the pieces to end up with 90º position changes. However, after the first move it became apparent that this was not quite so simple - the end positions are always at 90º from the start of a move but to achieve each position change requires very slight angulations to get the bulkier sections of each piece past obstructions. The moves need to be very very precise. This frightened me a little as my usual to and fro technique often resulted in me really struggling to undo a move or sequence. At one point during my exploration I tried to turn a piece in a particular direction and it seemed to be blocked. Stupidly I put a tiny tiny bit of force on it and it clicked past the obstruction allowing a whole bunch of new moves which didn't seem to help me. It had perturbed me that this had used force (albeit only a minuscule amount) so I thought I would backtrack again and realised I couldn't do it! Aaargh! Panic ensued and I had to put it down until the lunch break in the conference as I couldn't concentrate on both at once.

When I did return to the Cross, I spent a good ½ hour on it before managing to undo my stupid earlier move. Having learned my lesson (I can learn something once in a while but it has probably made me lose something else more crucial - there is not much room in my tiny brain!) Having got back to the beginning, I started again but tried to move in the opposite direction. The crucial move proved tough to find but I got there and after that managed to separate the pieces:

Finally! It took me a good hour or two
As you can see, the pieces are almost identical - only one has the required gap to allow them to be separated. I left the pieces for the rest of the day before reassembly which then took me another hour having forgotten the moves.

This is a really nice design by Edi Nagata who also designed the Cast Coil which was one of the first Hanayama puzzles I ever attempted and reviewed way back in 2011. Both are beautifully designed requiring a fun and well hidden sequence of moves. I think that the Cast Cross is probably the same difficulty as the Cast Coil (rated as 4/6 Hanayama and 8/10 Puzzlemaster) and I would tend to disagree with the difficulty rating for the Cross and increase it by one point. It is definitely one that should be in your collection. I would suggest that it probably should not be handed to non-puzzlers to play with because if forced then it may be irrevocably locked up.


  1. As I recall, Edi had a prototype of this puzzle as his exchange one year. I 3D printed a copy for him, and at one point he was selling 3D printed copies of it. It looks very nice in metal, I think he also has tweaked the design a bit.

    1. I had no idea! He must have a very peculiar brain to be able to design something like this!