What is Jiao Gan / Jiao Yanshou?

Jiao Gan (焦贛), also known by his courtesy name Jiao Yanshou (焦延壽), is a Western Han dynasty scholar (c. 1st century BC) to whom the Yilin (Forest of Changes) is attributed. A specialist in I-Ching consultation who served as a local official, he was the teacher of Jing Fang, who later formalized the Liu Yao najia system. Jiao Gan's Yilin represents the literary tradition of I-Ching interpretation; his student Jing Fang created the structural analytical tradition.

Source: Han Shu (漢書), Biographies of Scholars, Vol. 75