Shown mark is that used on items by the [b]Charles Sadek Import Co.[/b] ( “Andrea by Sadek”, etc. ) which was established 1936. It is found on items made in Japan following World War 2 (1950s-1960s); Sadek never made items themselves.

As the mark was applied to items Sadek ordered from various manufacturers and the same mark was used unchanged well over ten years, you remaining questions can not be answered.