Who is Nobusuke Tagomi from The Man in the High Castle and what is their importance?

Tagomi is a high official with the Trade Mission of the Pacific. Tagomi does a great deal of business with Childan in order to add products to his own collection and to buy gifts for business associates. Tagomi buys a Colt .44 from Childan that he likes to use as a gunslinger might have in the old days of America.