Song Ik-pil (Korean: 송익필, February 10 1534 - August 8 1599), also known as Unjang, was a Korean scholar, writer, politician, and Neo-Confucian philosopher of the Joseon period.
His nickname was Gubong (구봉, 龜峰) and Hyeonseung (현승, 玄繩).[source?]