The letter is more personal and carefree, rather than a formal piece of writing. "It is also full of variety in the style of characters," notes Chen, "and is considered a dexterous piece honed by Zhao in the late stage of his career."

The national museum temporarily closed its doors on Jan 25 as part of measures to curb the spread of coronavirus. It reopened on May 1 under strict conditions, including pre-ordered ticket holders only, and a daily cap of 3,000 visitors.

Gu Bo, who works at a tourism company in Beijing, was among those who visited the National Museum on the day it reopened. She says she was most impressed by the first national flag of the People's Republic of China, which is on display at the ongoing Stand in the East exhibition. It shows objects and works of fine art marking the founding of the PRC.

Gu says she was surprised by the flag's size. Measuring 4.6 meters in length and 3.4 meters in height, the flag was raised at the PRC's founding ceremony on Oct 1, 1949.