Wednesday 21 December 2011

Sheffield Steel 6BB

Sheffield Steel 6BB
By now, you all know how much I love wooden puzzles (actually all puzzles) and I have a particular penchant for wooden burr type puzzles. So when I put in my last order at Puzzle Master, I just couldn't resist this one - particularly because I live in Sheffield (the home of the UK steel industry). This is called Sheffield Steel 6BB presumably because the pieces, in cross section, look rather like steel girders. I assume that the 6 denotes the number of pieces in the burr but I have to say that I have no idea where the BB comes from.

It was originally designed by Ronald Kint-Bruynseels, a rather prolific puzzle designer who seems to have specialised in burr type puzzles. The original version and the one reviewed here is manufactured by the German puzzle/toy company, Philos. In 2006 one of my favourite puzzle craftsmen, Eric Fuller, produced a limited edition run of this puzzle in a variety of different woods (I cannot tell what wood the Philos version is made from). His versions look absolutely stunning. I would love to obtain a copy of Eric's - if anyone has one for sale then please contact me.

Eric described this puzzle as follows:
"The beauty of his designs is that he achieves incredibly high level puzzles with relatively simple shapes. While simple, the high precision necessary due to the extreme degree of interlock makes producing his puzzles a challenge. Sheffield Steel 6BB is no exception. This beautiful and unconventional puzzle has a unique level 17.14 solution. An incredibly difficult puzzle that can easily be displayed as a work of art once solved."
I could not describe it more eloquently than this - It is a lovely shape and truly difficult to solve. It is 10 x 10 x 10cm in size and, at least in my version, is pretty loosely held together which gives the false impression that it should come apart very easily. It arrives in a very nice Philos box with the puzzle on display - this would definitely make a good present for the puzzler in your life. It does come with a solution in the box but if you lost it and want to download a new copy then you can get it from here. I have created a Burrtools file for it to confirm that there is only one possible assembly - if you would like a copy then just contact me and I can email you a copy.

When I started playing with this, I expected to take it apart quite easily - partly because I have had a lot of practice with burr puzzles now and also because it was so loose that you can see the interior quite easily. I was very wrong - it takes 17 moves to remove the first piece and it took me nearly an hour to master. Some of this time was due to me constantly back-tracking to ensure that I remembered the pathway but also because there are quite a few dead ends on the way - it takes some time before you realise that you are actually in a dead end due to the looseness of the pieces giving the impression that further movement is possible. The first piece came out, much to my relief, and I was very careful to ensure that I kept the orientation noted for reassembly.

I thought that it would be easy from here on - Oh how wrong I was!!! It is supposed to be another 14 moves to take this piece out and I really struggled with this. I quickly discovered that the second piece could be removed with a single rotation but this is cheating! The correct sequence of moves actually took me another 2 or 3 hours to discover (oh the shame!!!). The process is really tough, partly because being so loose meant that nothing would stay in place whilst you searched for the next slide. But the main reason for the extreme difficulty is that it effectively requires 2 goals - first to move one piece out of the way and then to actually extract the second piece.

The final pieces require 5, 2 and 3 moves to achieve complete disassembly and are not particularly difficult.

6 Pieces
The reassembly would be impossible for me had I not arranged the pieces in order and spent so much time back-tracking during the solve process. I am sure that my puzzle friend, Guillaume Largounez, would be able to reassemble this by true analysis of the pieces, but no amount of reading of his 6 piece burr analysis paper has helped me be able to do this. One day, I hope to meet him in person and he can actually take me through the process step by step. Only then will I become the burr puzzle solving machine that he is!!

This is a really wonderful burr puzzle, well worth the $34.50 that Puzzle Master charge for it - it is good for beginners and experienced puzzlers alike and even having solved it, I still enjoy repeatedly opening it.

I find it rather odd that a European company seems to have absolutely no outlets in the UK - it is easier to buy this from Puzzle Master than from Philos themselves! If you can get one of Eric Fuller's versions then you know it will be absolutely gorgeous as well as terrifically difficult.

Eric, if you read this and have one left over - you know where I am!!!!


  1. Thanks for this review Kevin, this puzzle just climbed on my wishlist.
    For your (and you readers) information, several Philos puzzles including this one are also available from a shop near my home:
    That's not in the UK either, but it's close. And free shipping to any puzzle party that I happen to attend.

  2. The reason the paper doesn't help as much for this, is that this is a board burr (thus the bb), which I believe is referred to as such because the burr surface is flat, with multiple possible depths of cuts in a single surface.
    A couple commercial (and plastic) board burrs are Gordian Knot and Zig Zag Knot...

  3. Ah! I wondered what the BB stood for!!!

    So the general approach that Guillaume wrote down is not applicable to board burrs? I should have guessed that.

  4. Hi Kevin

    you are not completely right with the first production of this burr; have a look at:
    we offerd it in 2004 at the website of
    we got the permission from Ronald to make a small batch of all his very interesting burrlike puzzles


    1. Thank you for the correction, Bernhard. Your version looks much nicer than my Philos one!