1931 (May 31) registered First Flight cover, endorsed “First flight Eurasia airmail Peking to Manchouli”, franked on front Second Peking print Air Mail issue 30c. black & deep red, and 1923 Second Peking print Junk issue 2c. yellow green, horizontal pair, and 6c. scarlet, tied by five strikes of “Founding of International Air Mail Commemoration, PEIPING 1931 May 31” special commemorative cachet, on reverse with “Founding of International Air Mail Commemoration, Manchouli 1931 June 1” special commemorative cachet and PEIPING 1931 June 5 cds, fine. Start price $200 (Image)