BEIJING, July 4 -- A post office opened for business Friday in the Museum of the War of the Chinese People's Resistance Against Japanese Aggression in Beijing.

The post office consists of two parts, a physical post office and an online one, according to museum staff.

Customers can send and receive letters in the bricks-and-mortar post office and buy commemorative envelopes, postcards, and stamps with unique postmarks.

The same products are also on sale online to cater to the demands of stamp collectors worldwide.

The new post office is not only a platform for disseminating the history of the Anti-Japanese War but helps people find out about the spirit and the history of the war.

Japan invaded northeast China in September 1931, but the full-scale invasion started on July 7, 1937, when a crucial access point to Beijing, the Lugou Bridge, was attacked by Japanese troops.