Sun Xin, nicknamed the “Little Yuchi,” is a Liangshan hero in Water Margin, the younger brother of Sun Li, and the husband of Gu Dasao. He operates an inn in Dengzhou and belongs to a close regional network of relatives and martial companions.
When the brothers Xie Zhen and Xie Bao are framed and imprisoned after the tiger-hunting dispute, Gu Dasao decides to rescue them. Sun Xin joins the plan and helps bring Sun Li and other relatives into the operation.
After the Dengzhou group breaks the prisoners out, they can no longer remain safely in the region and eventually make their way to Liangshan. Sun Xin thus enters the brotherhood as part of the larger Dengzhou group.
At Liangshan, Sun Xin and Gu Dasao remain associated with inns, support work, and military activity. Following the imperial amnesty, he takes part in later campaigns and survives the wars. His role is closely tied to Sun Li, Gu Dasao, and the family relationships that help bring the Dengzhou heroes into Liangshan.
