From the liner to the frame to the button and so many more, there are a ton of different knife locks out there.
It is such a rich category that my colleague Sean Tirman wrote an excellent breakdown of the most common types last spring.

However, in all our collective years of collecting and writing about knives, neither of us has encountered a mechanism quite like the one appearing on the Midgards Messer Bragi Mini Folder.
This tiny knife’s unusual name, functionality and mystery compel me to explore every little aspect of it, so let’s go.
Don’t stop the Beets
Like many knife enthusiasts, I love a tiny knife, with WESN’s Micro Blade, The James Brand’s Elko and Gerber’s LST Mini being among my favorites.
But while those three carry pretty straightforward locking mechanisms (a frame lock, slip joint and lockback, respectively), the Bragi is bringing something different.