While the numbers on the front dial give it the classic look of a combination lock there are other features of the puzzle that put it firmly in the trick opening puzzle category.
This is one of the hardest from German puzzle makers Siebenstein-Spiele with a rating of 7 stars (out of 7!).
Brian (aka Mr Puzzle) spent many hours on this puzzle but has still failed to open it. He eventually gave up and used the solution. Even though he did not solve it himself he did find that understanding the solution was quite satisfying and could appreciate how complicated the lock really is.
On our website at: https://www.mrpuzzle.com.au/lock-064-trick-opening.html