德川家治
In this highly controlled context, the traders became the sole official conduit for trade and for scientific-cultural exchanges between Europe and Japan. The VOC opperhoofd was accorded the status of a tributary of the shogun; Titsingh twice had to pay an obligatory annual visit of homage to the shogun in Edo. Given the scarcity of such opportunities, Titsingh's informal contacts with bakufu officials of Rangaku scholars in Edo may have been as important as his formal audiences with the shogun, Tokugawa Ieharu.