Thursday 18 August 2016

Sliding Block Puzzle Locks

Some weeks ago puzzle collector Otis Cheng from China had mentioned on his Facebook post that he had acquired two sliding puzzle locks that had been designed by a group of students from a Beijing 12th grade middle school. The students had designed the locks with the help of their teacher who happened to be a puzzler! 

I thought they look pretty impressive and a rather unique approach to a puzzle lock design. But thanks to Otis I managed to get my hands on two such puzzle locks when I met him at IPP36 in Kyoto this August.

Both lock designs were adapted and eventually mass produced by Mi-Toys. The two locks are about the same size measuring 11cm x 7.5cm x 1.5cm (including the shackle) with one a tad smaller than the other. They are layered and formed together with laser cut wood. The moving blocks within are covered by a clear acrylic cover with cut-outs sufficient for the acompanying key to aid in moving the blocks around inside the lock. Fingers would be too big for this the key actually serves a useful purpose here!

The shackle of each lock is restrained by the blocks inside the lock. Both puzzles work on the principle of sliding blocks and once the blocks have been moved into their intended final positions, the shackle extends upwards and is freed.

Of the two puzzles one is relatively easy while the other (with more pieces) is quite a bit harder. While travelling back to Singapore from Kyoto, I took the opportunity to play with both locks and thankfully managed to solve both during the one hour domestic flight from Osaka to Tokyo. Hence you will notice the less than acceptable photos of the solved puzzles as they were both solved on my lap during flight.

An interesting take on the traditional sliding block puzzle or puzzle padlock, or both, whichever way you choose to see it. As of this post, I can't seem to find them on the Mi-Toys site but I think eventually they will make their way there.


  1. These look very cool. I designed a few puzzles similar to these in Puzzlium (very cool app by the Grabarchuks), so I managed to solve the lock with L pieces from your first photo of it. The other one I may need to pick up!