a group of scholars commissioned by the emperor produced an expanded revision called the Guangyun. The Jiyun (1037) was a greatly expanded revision of the Guangyun. Lu's initial work was primarily a guide to pronunciation, with very brief glosses, but later editions included expanded definitions, making them useful as dictionaries.

Until the mid-20th century, the oldest complete rime dictionaries known were the Guangyun and Jiyun, though extant copies of the latter were