The collection of Dr Raymond Casey is to auction on December 12 in Geneva, led by the earliest known cover from the official Russian post in Peking.
Showcasing the finest stamps and covers from the Russian post offices in the Chinese empire, this is the second instalment of Casey's collection to have been auctioned this year - April's sale setting a $540,000 world record for Mongolian philately.
The cover in the present sale is expected to sell for $91,000-130,000.
The Russian post offices in the Chinese empire were first established by taking advantage of a mistranslation in the Treaty of Peking, which was signed at the close of the second opium war in 1860. Using "calculated deception", according to the auctioneer, the Russian government set up an illegal postal system named the Merchants' Post.
Around 1874 the Merchants' Post was incorporated as a legitimate arm of the Imperial Russian Postal Administration, with its main offices at Kalgan, Peking and Tientsin.
The cover is dated October 24, 1877 and was sent by notification to St Petersburg, bearing an 1866 1k and three 1875 10k stamps. Cancelled by a boxed Peking handstamp, it also features the St Petersburg receipt and wax nobility seal.
The earliest known cover from the Peking post office, it is in great condition aside from being slightly trimmed at the base.
In April's auction, the earliest known mail from any Russian post office in China - dated 1875 - sold for $124,726, suggesting strong results for the Peking cover.