It has quite clear marks showing it was made in Stockholm: the date stamp appears to be Y9, and the maker's mark is "ICO". However, I haven't found anything to indicate who ICO is/was, and "Maritschnig" turns up nothing either.




The date mark is slightly unclear: it could be either Y8 or Y9, but judging by the style the I think 1973 date is more likely. SWEDEN MARITSCHNIG is also impressed on the back of both sides of the clasp.
Does anyone know anything about "Maritschnig" (which is a German name, I would think) or "ICO"? Years ago I posted the same question to modernsilver and was told ICO might represent "Galerie 22" in Stockholm, but I never was able to learn more about them.
Many thanks for any information (again)!