Today in Postal History

This uprated postal stationery envelope was posted
in the treaty port of Shanghai using Hong Kong postal materials.

The envelope is preprinted with a 5 cent indicia.

A 5 cent light blue Victoria from the issue of 1882 (SG 35)
has been added to meet the rate to Germany.

There are no transit or arrival marks on the front.

Düsseldorf is about 50 km north of Köln in western Germany.

One might speculate the reason for a German letter to be sent
through the British Post Office system rather than the German system.

The British Post Office in Shanghai was opened in 1844.
The German Post Office opened in 1886.
There were also French, Japanese, Russian, and American Post Offices there.