Hong Kong. (Treaty Ports). 1878. Envelope addressed to Switzerland bearing Hong Kong SG 12, 12c pale blue tied by 'Y/ 1' obliterator with adjacent Yokohama/ A date stamp 'Mr 4 78', endorsed 'via Brindisi' with Hong Kong transit 'Mr 12th' on reverse. bold Brindisi '17 Apr' and Dubendorf arrival '20th Avril' on reverse.
The British concession and trading in Yokohama was very prosperous yet the number of surviving covers is less than 200, far smaller than those of the French Post Office in Yokohama.