Taken from: Paul Wheatley: Geographical notes on some commodities involved in sung maritime trade.

Empress Liu Kuei-fei (1) refused to pay the very high sum of 30,000 strings of cash (2) demanded by a foreign merchant for two-tenths of an ounce (3) of ambergris.

Note: All authors agree that the Chinese only got to know Ambergris through the Arabs and that they were unaware that the substance was also found on their own coast. The Arabs collected Ambergris on all Indian Ocean coasts (including East-Africa).

(1) Liu Kuei-fei: concubine of the Emperor Kao - tsung , who died in 1187.

(2) strings of cash: used as a superunit of the Chinese cash (amounts of coins on the string fluctuated a lot)

(3) Ounces: here liang: traditional Chinese weight unit, about 37.8 grams, the same as a tael.