Tern Key

Name
Tern Key

Designer
Goh Pit Khiam

Manufacturer
Sold by Eric Fuller's Cubicdissection in 2009 for $49. Currently not available. New batch of Tern Keys expected to be released in the coming months.

Type & Classification
Sequential movement and take-apart.

Dimensions
14cm (Length) 9.6cm (Width) x 1.3cm (Height).

Materials & Construction
Acrylic, white nylon and stainless steel. The unit that is featured in this review is an initial production copy given by Eric to Goh, which will lead to a fresh batch that he will be making for release sometime soon. Construction fit and finish is excellent as per the usual Eric Fuller standards. The preision laser cutting has been carried out to very exacting tolerances. The sliding pieces all move smoothly although occasionally a piece may get a bit stuck but it takes just a slight tug to get things going again. Overall you have the look and feel of a high quality expensive puzzle.

Overview
Tern Key was another puzzle that was loaned to me by fellow Singaporean and puzzle designer Goh Pit Khiam who to-date has designed around sixty puzzles, many of which have been produced and are now in the hands of puzzlers and collectors worldwide.

The Tern Key is similar to the La Cerradura Doble by Robrecht Louage reviewed earlier in this blog, but both have different methods of solving.

The Tern Key is also a "harder" version of Goh's earlier wooden Key Puzzle (Eric will also likely be releasing the Key Puzzle in acrylic format together with the Tern Key). As Eric described during the first release of this puzzle... "The original Key Puzzle used a binary locking mechanism. Tern Key ups the ante with a trinary implementation, yielding a hefty 134 move solution with four locks!...."

I have never played with the earlier Key Puzzle so I jumped straight into the deeper end with the Tern Key. The object of the Tern Key is to slide the U-shaped key out the right side of the puzzle. The key is locked in place by four "locks" formed by sliders. One has to manoeuvre the sliders of each of the locks left, right, up and/or down to unblock and release the key. The locks cannot be worked on individually one at a time as the movement of sliders of one lock will either restrict or allow the movement of the sliders of an adjacent lock.

Given the interplay of the sliders and locks, one is required to think a number of steps ahead during the solving process. There were several times I found myself almost at the finish, only to be blocked by the last lock and I have to retrace my steps back to the beginning and start over again.

Although there are 134 steps needed to extract the key, a number of these are repetitive. Whether I really made 134 moves I honestly wouldn't know. My main aim was just to get the key out!

Difficulty Level
Very challenging but not unduly difficult. Took me the better part of a couple of hours to remove the key.

Summary
A very enjoyable puzzle and I had great fun with it. You can see clearly all that is happening through the transparent acrylic as you go about the solving process. You get a sense of achievement as you pass each lock and then that a-ha moment when you finally free the U-shaped key. Definitely worth acquiring both from the quality standpoint and puzzling perspective.