Convert from hair's breadth to ch'ih [China]

Unit Definition (hair's breadth)
The hair's breadth is a common informal unit of distance. Human hairs vary considerably in width, depending on age, color, genetics, and other factors. An average hair is approximately 70 to 100 micrometers (µm) in diameter, so, as a rough standard, a hair's breadth is 100 µm or 0.1 millimeter (mm).

Unit Definition (ch'ih [China])
The ch'ih is a unit of distance used in China during the colonial period. The ch'ih equals 10 t'sun, 35.814 centimeters, or 14.1 inches. There are 1800 ch'ih in a li.