  The so-called \textit{China crisis}, well documented in \textit{History of
the IAU} by Adriaan Blaauw and in \textit{Under the Same Starry Sky: History of
the IAU} by Chengqi Fu and Shuhua Ye, refers to the withdrawal in 1960 of the
People's Republic of China (PRC) from the Union. The crisis stemmed from the
admission by the IAU, amidst strong protest from PRC and some other member
countries, of the Republic of China (ROC) to the Union, creating the so-called
`\textit{Two Chinas}' -- or `\textit{One China, one Taiwan}' problem. The
crisis directly led to the absence of mainland Chinese astronomers from the
stage of international collaborations and exchanges, and was only solved two
decades later. The solution, accepted by all the parties involved, is that
China is to have two adhering organizations, with mainland China astronomers
represented by the Chinese Astronomical Society located in Nanjing (China
Nanjing) and China Taiwan astronomers represented by the Academia Sinica
located in Taipei (China Taipei). The denominations `\textit{China Nanjing}'
and `\textit{China Taipei}' represent the IAU official resolution and should be
used in all IAU events.
  The China crisis, probably the most serious one in IAU history, was a painful
lesson in the 100-year development of the Union. Yet, with its eventual
solution, the Union has emerged stronger, upholding its spirit of promoting
astronomical development through international collaboration of astronomers
from all regions and countries, regardless of the political systems, religion,
ethnicity, gender or level of astronomical development.
