Wednesday 27 April 2016

Chain Store

Chain Store

Goh Pit Khiam

Manufacturer & Availability
Crafted by Tom Lensch. Limited copies may be available but I can't be sure. PM me if interested.

Type & Classification
3D Packing

Box is 5cm x 5.7cm x 6cm. Each of the links in the chain is 4.7cm x 3.1cm x 0.8cm.

Materials & Construction
Box is yellowheart while the chain links are cherry. Excellent construction, fit and finish. Tolerances are just right and everything fits nicely.  

Chain Store is an old design from Goh Pit Khiam and it wasn't until recently that working copies of the puzzle were produced. The goal is simple; to fit the chain links (which are all interconnected and you can't separate them) into the box flush with the top. Hence the very appropriate name "Chain" - "store". It's been described by John Rausch as a "one piece packing puzzle"...well, quite literally true isn't it?

The links when stretched out look rather long and it is obvious that you can't just stuff them into the box. Because of the tight tolerances, any attempt to force in the links would most certainly result in jamming (and probably damage as well). According to Goh, there is only one solution to pack the links in. Sorry but Burr Tools doesn't work here (even with the "grouping" function).

It is clear that the links must somehow be grouped together in a certain way to take up the smallest and correct size footprint in order to fit into the box just nicely. The links can be rotated in different ways and this is a necessary part of the solving process. But this arranging and grouping of the links is no walk in the park, despite only 5 pieces. In fact it is darn right difficult and I found myself trying a great number of combinations to no avail. Always, one link would be protruding a bit and refuse to go in the box. This puzzle requires you to solve the links outside the box before insertion.

Very challenging puzzle. I don't know whether it was just my lucky day or not, but I managed to solve it in about 40 minutes. Got the 5 links all in their correct positions and popped it into the box. Still, I can imagine some puzzlers would take much longer than that. At the request of Goh, I have not placed a link here to the photo solution. 

Goh has designed a number of challenging and interesting packing puzzles, including IPP award winning ones such as Dancing Shoes and Road Blocks. But Chain Store is perhaps the most unusual and unique amongst them. A fabulous puzzle with a great design concept.  A must-have in any collection.


  1. Nice puzzle! Unfortunately Tom does not have any left. It would have been very fun that the wooden chain was made with only one piece of wood, but maybe way to hard to craft...


  2. I have seen several solve it in less than five miniutes and some take days. That's puzzling too.

  3. Crafting that chain out of a single piece of wood would be incredibly difficult. Tom probably has nightmares about that.