Zi Collection, Upper Volume, Page 15, Entry 04 Pronounced yu zhao (falling tone), same sound as "zhàn". "Book of Categories (Leipian)" records it as the name of an insect. Also, "Zhengzitong" states it is the same as the character "yáo". Quoting "Six Principles of Characters (Liushu Gu)": It is like a clam, whose adductor muscle is most prized. See also Jade Radical.