OK, guys, many thanks for the compliments, but they are misplaced.
The Black Sea origin of the BSY was known to many ( Artzi, for sure!) well before my trip to Istanbul. The presence of similar specimens in the Askeri Muze was also mentioned by others.
My only "contribution" was asking a young curator there the local name for it, and reporting here that it was Laz Bicagi. Beyond that, I added zilch to the issue.
As to the term "yataghan", it also comes from the origin: "Black Sea Yataghan" is a literal translation of "Karadeniz Yataghan". Astvatsaturyan in her book "Turkish weapons" shows a gorgeous example with ivory handle ( BTW, more "ear-like" than the usual horns) from the collection of the State Historical Museum. The caption reads (in exact translation) " Yataghan of original form". I already had a short fistfight with a non-Russian enthusiast who wanted to announce an Earth-shattering theory that this type of sword was in fact an "Ur" yataghan, based on the literal translation of the word "original". In fact, Russians use the word "original'nyi" to indicate " unusual".
As the mouse said after barking at the cat and frightening it into immediate retreat " It is nice to know foreign languages"
BTW, can the moderators permanently attach a picture of Artzi's kindjal to this thread? Hope he does not mind.