Civil official who led volunteer troops at Yeongcheon in the Imjin War; pen name Manchwidang; Seonmu Wonjong merit subject

| Life | 1548 ~ 1603 |
| Era | 조선 중기 |
| Clan | 연안 김씨 |
Kim Gae-guk (1548-1603) was a Seonjo-era civil official of the Yeonan Kim clan, with pen name Manchwidang, born in Yeongcheon, North Gyeongsang. He studied under Bak Seung-im, a disciple of Yi Hwang.
He passed the licentiate exam in 1573 and the civil examination in 1591. When the Imjin War broke out the next year he returned home and raised volunteer troops as a leader. He was specially appointed to the Yebinsi in 1595 and rose to magistrate.
Politically he moved from the Easterners to the Northerners and then, with Yu Mong-in and Nam I-gong, to the Lesser Northerners. Known for refusing to bend on principle, he is said to have lived an unlucky life. He was named a third-class Seonmu Wonjong merit subject in 1605, posthumously promoted and enshrined at Sambong Seowon in Yeongcheon in 1643. His works include the Manchwi Ilgo.
In July 1592 Kim Gae-guk stayed and raised volunteer troops at home; for this he was named a third-class Seonmu Wonjong merit subject after death.
Manchwidang in Yeongju is the building representing the Yeonan Kim of that region and Gyeongbuk Cultural Heritage Material No. 451 (2003); the clan's books and printing blocks kept there are Gyeongbuk Tangible Cultural Heritage No. 346.
His tomb location was not confirmed. Manchwidang, the hall named for his pen name, stands in Sinam-ri, Isan-myeon, Yeongju.