

The earlier Y19 uses the proper kana To, for founder Yamamoto Tosuke, and is traced to 1901. The later Y2 uses a stylised form. Alan Watt identifies Y2 as the post-war version, while Jordan indicates replacement of Y19 by 1939. Merchant Ships 1942 references Y19 in its fleet list but does not reproduce it in the funnel section; a monochrome Konzan Maru photograph appears to support that design.
The Osaka company originated as Yamamoto Tosuke, also recorded as Yamamoto Toshi in hiragana on a 1903 sheet. It operated before the Second World War and continued until about the mid-1960s.
Japan, Osaka.