Lot 10155 – ULYASUTAI: 1920 10k Postal stationery envelope sur

ULYASUTAI: 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. Note: Illustrated in « The Postal History of Mongolia » p.69 by Hellrigl and described as one of the rarest items of Mongolia’s postal history