Imperial units commonly used units for length are (li), (tseung/cheung), (tsek/chek), (tsun/chun), (fen/fan) in descending scale order. These units are now rarely used in daily life, the imperial and metric systems being preferred. The imperial equivalents are written with the same basic Chinese characters as the Chinese system. In order to distinguish between the units of the two systems, the units can be prefixed with "Ying" () for the Imperial system and "Wa" () for the Chinese system. In writing, derived characters are often used, with an additional (mouth) radical to the left of the original Chinese character, for writing imperial units.
The Imperial Physician "The Imperial Physician" as an example of how Pu shows that "the dialectics of unexpected but reasonable change of things is not only used in events concerning supernatural power, but also human life". "(T)hat things go from the expected to the contrary direction", as seen in how the imperial physician's advice is dismissed given the rarity of bear and tiger meat, yet Sun Pingshi meets such an "unexpected but fatal" death nonetheless. The Imperial Physician "The Imperial Physician" () is a short story by the Chinese writer Pu Songling collected in "Strange Tales from a Chinese Studio" in 1740, and