Thursday, 26 April 2018

Endo-san’s KOPA

KOPA, or KO Box has been my go-to puzzle for inflicting on random puzzlers for a good few months now – it has a great balance between looking innocuous and managing to convince you it’s totally impossible… and pretty much everyone who’s solved it, absolutely loves it! 

Takeyuki Endo makes fabulous looking puzzles – quite often lavished with superb decoration for no reason other than to make them look pretty, REALLY pretty! 

His puzzles generally have a bit of a twist, or several challenges… KOPA is a simple, single challenge puzzle: assemble the box, with a little drawer-piece in the centre – that is all.

There are three pieces making up the box, and one more piece to go into the centre… two of those box-pieces are permanently joined (back right in the picture above), and one piece can be introduced and removed at will while the central drawer-piece (front, centre) isn’t in play… The movements are governed by tracks and dowels in the respective pieces – and the whole thing ends up working a bit like a universal joint. 

That central drawer-piece is symmetrical and can go into the middle box-piece a few different ways – with exactly the same result… there’s no funny business in there, it really is as honest as it looks. 

Inserting the drawer restricts the movement of the final piece to the extent that you can almost close the whole she-bang up neat and tidy, but not quite. 

And therein lies the puzzlement. 

Without that drawer-piece, assembly is trivial. 

With that drawer-piece, you’ll easily convince yourself that it is thoroughly impossible.

The mean time from picking it up to convincing yourself it’s impossible seems to be about 10 minutes for the puzzlers I’ve tested so far… 

…from there through to final solution has a somewhat wider distribution!

Some took weeks, others took minutes… 

Everyone agrees it’s a superb puzzle!

Great fun to pass around to puzzlers who haven’t seen it with a “Here, you’ll like this one… it probably won’t take you very long, but see what you think of it.”

I find I generally really like Endo-san’s puzzles – but this one became a favourite after Big-Steve spotted it on Torito’s website and ordered us a few… I’m very glad that he happened upon it and thought of me when he was ordering one… Thanks mate!


  1. I agree with your Review; I´ve got one on the German Cubeday and have now to try solving it

    1. ...the A-HAAA! moment is superb on this one, Bernhard!

  2. Hello Allard,

    As always, a very nice review - and a wonderful looking puzzle. I'm only wondering how you managed to get your copy since the welcome page on the Torito web site clearly states they will not ship to overseas countries any longer...

    1. Thanks Lionel! Torito won't ship internationally, but there would appear to be companies who will facilitate shipping for them and for places like the Japanese version of eBay... my mate Big-Steve takes care of the logistics for me.