I first stumbled across a set of three 4*4*4 cubes by Mineyuki Uyematsu (or just Mine) at Wil Strijbos’ place last year – he described them as quite interesting and admitted that he hadn’t solved them yet, which was all the encouragement that Louis needed to throw himself at one of them … however by the time we left that evening, it remained unsolved.
The next day I happened to spot one of them (Lock-Y-Cube) in Bernhard Schweitzer’s crate of unusual puzzles at the Dutch Cube Day and helped myself to it (having paid, promise!) – I left it in Eindhoven for Louis to solve and he duly brought it back to me in December having done exactly that (apparently the mechanism was a bit ‘rusty’).
At the end of December, Wil nominated these three cubes as one of his puzzle finds of the year at Peter Hajek’s EPP, still claiming that he hadn’t solved them yet (yeah, right!). When Wil mentioned he was going to spend some time in Japan, I asked him if he’d be able to pick up copy of the other two cubes in the set for me, and a couple of days after he returned from that trip I had a copy of the Disjointed Cube and the Lock-N-Cube in my grubby paws. (Thanks Wil!!)
I’ll start with the Disjointed Cube as it’s the least sneaky of the cubes. Playing around with the cube you’ll quickly distinguish a few pieces and find that you can expand it in one direction and create some space to fiddle around with the other pieces, a bit, but not enough to really be useful. I played with it for a little bit before I noticed something a little unusual and then found I was able to remove a piece (which actually surprised me at first!).
Having dispatched a piece, a little more movement becomes available and some manipulation will successively release the rest of the pieces.
Reassembly is reasonably straight-forward as there’s only really one piece that has to go in last and unless you’re incredibly creative, I think there’s only one way that the pieces can fit together to form a cube.
I found it quite an interesting design as it needs you to keep your eyes open and not just do the obvious, linear sort of things that you are probably programmed to do – well I am anyway!
The two Lock-Cubes are made in contrasting green and white woods with their patterns reversed, so there’s a bit of a clue that they may be related in some manner. Both cubes will expand in a similar manner to the Disjointed Cube, but that’s where the similarity ends!
These cubes seem to have pieces that are largely ring-shaped around the waist of the expanded cube, and the rings may slide up and down a bit, but they won’t do anything useful at all. There is literally no potential route out for any of the pieces… and that’s about as far as we got exploring them at Wil’s place – plenty movement – nothing useful.
Turns out they use a really sneaky, incredibly well-hidden little trick that stops you from making progress until you find it. The cubes are really well made though, so you can find clues to this lock, but you’re highly unlikely to actually spot it directly. Get past the lock, and all of a sudden there’s a whole new range of movement possible and in fact the pieces come apart fairly simply … and again, reassembly is reasonably straight-forward as there’s only really one way to build a cube from the sets of pieces, and there are few enough pieces so that the assembly itself isn’t too challenging…Nice set of cubes, and I suspect that offering them to a puzzler together, with a suggestion that they work on the Disjointed Cube first might just maximise the puzzling pleasure… and surprise.
Link to Mine's Shop for those who're interested - via Google-Translate: