Illegitimate-born writer, one of the Seven Friends by the River, whose false testimony triggered the Gyechuk affair
| Life | 1613 |
| Era | 조선 중기 |
| Clan | 부여 서씨 |
Seo Yang-gap (d. 1613) was a Joseon writer of the Buyeo Seo clan, recorded as an illegitimate son of Seo Ik. Dissatisfied with discrimination against secondary-born sons, he associated with fellow outcasts such as Bak Eung-seo, Sim U-yeong and Yi Gyeong-jun, styling themselves the Seven Friends by the Riverside on the Soyang River.
In 1612 he was arrested after killing a silver merchant at Joryeong Pass and robbing 600 to 700 nyang of silver. Lured by the Great Northerners Yi I-cheom and Jeong In-hong with promises of mercy, he falsely testified that he had plotted with Kim Je-nam, father of the queen dowager, to enthrone Grand Prince Yeongchang, setting off the Gyechuk affair. He was executed in 1613 regardless.
The affair killed Kim Je-nam and Yeongchang and led to the queen dowager's confinement. His acts should be read against both the social discrimination against secondary sons and the Great Northerners' manipulation of the case in a struggle for power.
Secondary-born sons could rarely reach high office. Seo Yang-gap and six others consoled each other on the Soyang River, sometimes styling themselves a bamboo-grove circle.
Arrested in the 1612 Joryeong case, he gave false testimony after the Great Northerners' inducement, and it grew into the case against Kim Je-nam and Yeongchang. He himself was soon executed.
No tomb is known after his execution.