here's a recent hand made bulgarian friction folder.
and some ring-locks
the kudu is a cold steel copy of the okapi, with fancier hardware & a modern glass reinforced zytel handle.
the okapi, made in so. africa, was originally made in solingen, but they licensed it to SA, the other large one with the more abrupt clipped point has an outline eagle head in a circle in a square stamped on the blade. i think it's an earlier german one. the teeny one (2in. blade) with the horn handle is an older spanish variant.
they are a variation on the ratcheting navaja design from spain, here is a six and a three inch blade version, the lever near the pivot lifts the lock pawl, similar to the ring pull type. there are five ratchet teeth the pawl clicks over on opening, preventing it from being pushed back and closing on the owners hand in case of a fight. the lever normally lies flat against the back of the grip, is raised 90 degrees to unlock the blade for folding. i've partially lifted them here for clarity.
they say the sound of the lock pawl clicking over the ratchet teeth was the scariest sound , and for some the last sound they ever heard, in a spanish bar...
the okapi is known to have killed more men in so. africa than any other knife.