Hi Nihl:
Ariel may be able to help with your question about origins of the
laz bichaq.
You mention atypical examples of the
laz bichaq (a.k.a. Black Sea yataghan), and I think I have one (presently buried deep in my boxes that were moved not long ago from the U.S. to Australia). Attached is a group picture that shows this sword (second from right), flanked by two more
laz bichaq of typical form. The sheathed one has three groups of three fullers, similar to other examples shown on this site.
I have also shown a close up of the unusual hilt. Apologies for the grainy picture, but it's the best I have at the moment.
Ian
P.S. This unusual sword was actually discussed previously on the Forum
here and I see that I never got around to posting pictures of it (only the auction link). I will try to dig it out of the collection and post much clearer shots.