I found some information on line about a fellow named PATRICK DESPATURE who has written and photographed what looks to be a nice book on tin plate planes made between 1910 and 1960. Just do a search and you will see the information, I have not seen the book so I cannot review it personally.
In reading some of his quotes on line, it seems that "ET Co" (Eichiro Tomiyama) sold toy airplanes outside Japan on behalf of other manufacturers such as Nomura in the 1930s, before its more famous association with Yonezawa (1950s-early 60s).
Most of the toys are pre-WWII and look as though they're in great shape.
