A great scholar of the mid-Joseon period who embraced and carried on the learning of both Toegye and Nammyeong; art name Hangang (寒岡)
| Life | 1543 ~ 1620 |
| Era | 조선 |
| Clan | 청주 정씨 |
Jeong Gu (정구) went by the art name Hangang (寒岡) and was born in Seongju, North Gyeongsang Province. Having studied Neo-Confucianism under both great masters Yi Hwang (Toegye) and Jo Sik (Nammyeong), he embraced both scholarly lineages of the Yeongnam school. A civil official and Neo-Confucian scholar, he was broadly learned in ritual studies, history, medicine, calligraphy, and many other fields.
He served as magistrate of several counties and as Inspector-General (Daesaheon), among other posts, and raised a righteous army during the Japanese invasions (Imjin War). In ritual studies he proposed the principle that the rites of the king and those of the scholar-officials differ (wangsabudongnye, 王士不同禮), and he also devoted himself to compiling local gazetteers and medical texts.
He trained some 300 disciples, including Heo Mok and Yun Hyu, forming the wellspring of the Geun-gi Namin (Southerner) scholarly lineage of late Joseon. His works include the Oseonsang Yeseol Bullyu, the Simgyeong Balhwi, and the Hangangjip. His posthumous title was Munmok (文穆).