Yang SW55-SW58 Southwest China, 1950 (14 Feb.) Kunming overprint on Silver Yuan Unit issue "Surface Mail" orange-brown (rouletted and perforated), "Express" magenta and "Registered" carmine, complete set of four

Yang SW55-SW58 Southwest China, 1950 (14 Feb.) Kunming overprint on Silver Yuan Unit issue "Surface Mail" orange-brown (rouletted and perforated), "Express" magenta and "Registered" carmine, complete set of four