Here is an extract from the post-auction report.

The full listing is available here.

David Feldman S.A. held its Specialised Auction on December 12-15, presenting two important collections: Part II of the Dr. Raymond Casey Collection of Russian Post Offices in Chinese Empire and the Part III of the Anatoly Karpov Collection of Belgium.The collection of the Russian Post Offices in the Chinese Empire, built over a duration of 60 years by Dr. Raymond Casey, produced incredibly spectacular results, including world record prices for Mongolian and Sinkiang postal history.This collection is the most comprehensive and extensive ever formed for this collecting area. After the fabulous results of our April 2012 sale which realised over EUR 1.4 million, the December auction surpassed our expectations with 94% of the lots sold for a total of EUR 2.6 million. David Feldman commented after the sale “Without doubt this is another one of the most successful sales we have had in our 45 year auction history! ”.Notable highlights:
Lot 10155 – 1920 Cover from Ulyasutai, Mongolia realised EUR 408,000 
Lot 10157 – 1917 Cover from Kobdo, Mongolia realised EUR 384,000
Lot 10159 – 1879 Cover from Kuldja, Sinkiang realised EUR 600,000The sale featured highly competitive bidding from collectors in David Feldman’s auction rooms in Geneva and Hong Kong as well as around the world via the Internet. Results were 500% greater than pre-sale estimates, and produced numerous world record prices, including one lot fetching as much as 175 times the catalogue estimate!After two outstanding Karpov Collection sales, the results of the third auction confirmed the robust demand for all areas from classic to modern as well as collections. The continued success of our Belgium auctions is perhaps due in part to our commitment of organising physical viewing of the collection in Brussels and abroad, which attracted large attendance.

Finally, our collector-oriented sale of Switzerland attracted keen interest, justifying our annual tradition to bring fresh properties to the local Swiss market.

Russian Post Office in the Chinese Empire: Dr. Raymond Casey Collection – Part II

China Proper

Lot 10021PEKING: 1877 (Oct 24) Cover sent registered by notification to St. Petersburg with 1866 1k and three 1875 10k, paying double the 8k rate, 10k registration fee and 5k for certificate of posting, cancelled by boxed Peking hs, reverse with ms despatch and Kyakhta arrival and St. Petersburg receipt, cover slight trimmed at base. This being the earliest known cover from the official Russian Post in PekingEstimated at EUR 70’000 and sold for EUR 204’000
Lot 10022 PEKING: 1880 (May 4) 8k Postal stationery cover to Austria, cancelled by “PEKIN’ / 4 MAY 1880” hs, with Kyakhta, Moscow and Vienna bs, taking 16 days to cross Mongolia and another 34 days to reach Moscow, one of only three known covers bearing this cancelEstimated at EUR 30’000 and sold for EUR 96’000

Mongolia

Lot 10155ULYASUTAI: 1920 10k Postal stationery envelope surcharged in ms “rub” (roubles) to pay the correct registered rate in depreciated currency, sent to Petrograd, cancelled by pen with Ulyasutai 27.5.20 type 2A cds (Hellrigl rated RRR, believed to be unique) adjacent, plus registration hs (rated RRR, also believed to be unique), Pertrograd bs, very fine and unique, also believed to be the latest date recorded of the entire Russian period, cert. British Society of Russian Philately.Estimated at EUR 40’000 and sold for EUR 408’000
Lot 10157 KOBDO: 1917 Native cover sent registered to Peking, franked with Arms 3k, 5k and 7k plus two 1916 10k on 7k, paying the 15k single letter rate plus registration, tied by Kobdo 2.9.17 type 1A cds, with reg’n label adjacent, Irkutsk censor hs, fine and very rare. One of only four covers recorded from Kobdo and one of the great rarities of Mongolian postal history.Estimated at EUR 70’000 and sold for EUR 384’000

Sinkiang

Lot 10159 KULDJA: 1879 Envelope sent registered from Kuldja to Taganrog (Russia), with 1879 7k pair tied by “KULDJIAN POSTAL BRANCH / PROVINCE OF THE SEVEN RIVERS” 24.05.79 cds with further strike above, Taganrog bs & manuscript annotation in Russian “Taken out of a (mail) box 24 May”, slightly reduced at top and some light soiling.Estimated at EUR 8’000 and sold for EUR 600’000
Lot 10166CHUGUCHAK: 1913 Chinese Imperial Post 1c postal stationery postcard uprated with 3c, sent from “Gorodok Dzhinysar” (Jinsar) via Chuguchak to Kazan, with Chuguchak 11.7.13 type 2A transit cds showing corrected spelling error “OBL.” (for Oblast), fine and possibly unique cancel. -Estimated at EUR 400 and sold for EUR 84’000