Security Lock

Security Lock puzzle lock designed by Liang-Jen Wu

The last several months, all the attention appears to have been showered on Rainer Popp’s very massive, very challenging and very expensive puzzle lock, the T11 Popplock. This week I had the chance to play with a somewhat more humble lock, the Security Lock designed by Liang-Jen Wu (Mister Wu) of Taiwan. The Security Lock was also Mr Wu’s IPP37 Exchange Puzzle in Paris last year.

The Security Lock is manufactured by German based board games and puzzle maker Siebenstein-Spiele. It measures about 13.5cm tall (including the shackle), 11.5cm wide and 1.7cm thick. It comprises three layers of laser cut wood sandwiching a single acrylic layer all screwed together. The overall quality of construction and fit is very good. All the pieces move and slide smoothly. The Security Lock also comes with a laser cut wooden key.

Security Lock puzzle lock designed by Liang-Jen Wu

A puzzle lock?

While the Security Lock is shaped like a lock with shackle and all, it is essentially a sliding block puzzle. This seems to be recent new trend in design. This lock is similar to two other wooden locks in my collection, using a sliding block concept. The “n-ary” locks  and their variants are still around and will remain so, as designers come up with new ones.

The body of the lock acts like a tray holding eight square and rectangle pieces. The layer of acrylic functions as a cover (with some cut-outs) to prevent the sliding pieces from being removed (in order to cheat). The blocks restrain the shackle in its place. The goal is to slide the pieces in such a way that the shackle can slide upwards and be freed.

The key has is useful too. Obviously it does not function like a real lock key does, but it helps to prod and move the blocks around inside the constrained space. The acrylic cut-outs are too small for most adult fingers to shift the blocks.

Security Lock puzzle lock designed by Liang-Jen Wu


The blocks can only move up down left and right. In the starting position, two blocks are obstructing the shackle. The shackle needs to slide upwards to the opened position. So obviously these two must move out of the way for the shackle to slide free. Hence the movement of the rest of the blocks in a certain way to achieve this. I cannot remember how many moves it takes to solve this “puzzle lock” but I would rate this puzzle as much more than a moderately difficult puzzle. Although not frustratingly so. I hit dead ends several times before I figured out the sequence of the moves.

Getting the shackle back to the starting position is a matter of reversing the steps, but similar problems persisted and I had to again try several times before everything went back to their original state. Puzzlemaster of Canada rates it as level 8 – demanding, but I think their assessment is a bit on the high side. I would rate it more a level 6.5.

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