Sunday 21 June 2015

Labour of love!

…that’s the only way to describe this masterpiece – truly a labour of love. 

Jack Krijnen designs some wonderful burrs – he is also a talented craftsman who’s been known to sell a few copies of his own designs at the Dutch Cube Day – I’ve been lucky to pick up a couple of them there and they really stand out: not only are they really interesting little burrs, but they’re little! 

Jack has found a sweet spot size-wise for creating puzzles for himself that gives an eminently playable puzzle, with all the accuracy of a larger copy, but at a significantly smaller size … which is probably important if you have a large collection of the things and plan to keep on designing and making more of them!

I jumped at the opportunity when Jack made a short run of Level 5 Burr sets about 3 years ago – I’d seen some pics of hundreds of little wooden sticks waiting to be burr-ified and knew I wouldn’t be sorry… and when Jack mentioned there might be another burr set in the future, I didn’t hesitate and piled in again.

This time Jack’s produced a copy of the Ultimate Burr Set featured in Botermans and Van Delft’s seminal “Creative Puzzles of the World”. The book uses this set to illustrate six piece burrs and includes a lovely description of JH de Boer’s exhaustive (manual!) analysis of the possible shapes of burr pieces and how they can be combined to give the familiar inter-locking 6-piece burr shape. 

Unfortunately the book makes no mention of how the pieces are selected for The Ultimate Burr Set, but does point out that 69 different combinations can be assembled into a 6-piece burr. (There may be slightly more than that... )

Jack has not only reproduced the pieces in a wonderful box (complete with tweezers and challenge cards, again), but he’s stepped up the analysis with the help of Ken Irvine and provided 59 combinations to produce a solid burr with no internal voids and a further 578 with internal voids – all sorted by level – right up to level 8!

In the interests of full disclosure, I have not yet constructed all of the possible assemblies (!) … I’ve constructed a fair few of them and the pieces are a delight to use – Jack has constructed each piece from a single piece of wood (I suspect it’s an honour thing! :-) ) – which is pretty awesome given the number of blind corners in there – and the fit is just brilliant. 

This is a set that will be bringing me many, many hours of joy (and no doubt plenty of perplexification!) … with some relatively simple level 1 challenges right up to the ones I’m unlikely to be able to solve in a month of Sundays…

The two Krijnen burr sets are slightly different sizes so you can’t mix and match pieces between them, but he’s kept the same style and inlays so it’s clear that they belong together – and they do look great together! This time the box is mainly mahogany and the pieces are maple… the attention to detail is pretty mind-blowing – it’s very clear these sets are quite simply a labour of love.

Thank you Jack!


  1. Shame I missed out on the original set! Maybe one day I will manage to get a level 5 set for myself!


  2. Jacks craftsmanship is something to behold. This looks like outstanding quality.