Hong Kong SAR in the context of "Japanese occupation of Hong Kong"

The high-speed rail (HSR, Chinese: 高铁; pinyin: Gāotiě) network in the People's Republic of China (PRC) is the world's longest and most extensively used. The HSR network encompasses newly built rail lines with a design speed of 200–380 km/h (120–240 mph). China's HSR accounts for two-thirds of the world's total high-speed railway networks. Almost all HSR trains, tracks, and services are owned and operated by the China State Railway Group Co. under the brand China Railway High-speed (CRH).

Since the mid-2000s, China's high-speed rail network has experienced rapid growth. CRH was introduced in April 2007, with the Beijing-Tianjin intercity rail, which became fully operational in August 2008, being the first passenger-dedicated HSR line. Currently, the HSR extends to all provincial-level administrative divisions and the Hong Kong SAR with the exception of Macau SAR.

Chinese units of measurement, known in Chinese as the shìzhì ("market system"), are the traditional units of measurement of the Han Chinese. Although Chinese numerals have been decimal (base-10) since the Shang, several Chinese measures use hexadecimal (base-16). Local applications have varied, but the Chinese dynasties usually proclaimed standard measurements and recorded their predecessor's systems in their histories.

In the present day, the People's Republic of China maintains some customary units based upon the market units but standardized to round values in the metric system, for example the common jin or catty of exactly 500 g. The Chinese name for most metric units is based on that of the closest traditional unit; when confusion might arise, the word "market" (市, shì) is used to specify the traditional unit and "common" or "public" (公, gōng) is used for the metric value. Taiwan, like Korea, saw its traditional units standardized to Japanese values and their conversion to a metric basis, such as the Taiwanese ping of about 3.306 m based on the square ken. The Hong Kong SAR continues to use its traditional units, now legally defined based on a local equation with metric units. For instance, the Hong Kong catty is precisely 604.78982 g.