“缅甸封”是指从中国云南省寄出的信函通过缅甸中转,与“西伯利亚封”、“印度封”、“安南封”相类似,只是仅见一件寄往美国的实寄封,尚未见有通过缅甸转回中国内地的实寄封。旅美华人集邮家张恺升在其编著的《中国邮戳史》第二册第420页上有一个盖“由缅甸转”字样的古封,也 “Myanmar seal” refers to a letter relayed through Myanmar from China’s Yunnan Province and is similar to the “Siberian seal”, “Indian seal” and “Annan seal” except that only one real seal addressed to the United States has been seen but has not been approved Myanmar sent back to China the real mailing. Zhang Qisheng, a Chinese-American philanthropist, wrote an essay on page 420 of the second volume of “History of China’s Postmarked Stamps”