Yu Shiji (虞世基; before 558 – 11 April 618), courtesy name Maoshi (懋世 or 茂世),[a] was a Chinese calligrapher, poet, and politician who served Emperor Yang of the Sui dynasty as a de facto chief minister from 607 to 618.
An astute politician and erudite intellectual, Yu was nevertheless faulted by traditional historians for personal corruption, indulging Emperor Yang's autocratic tendencies, and mismanaging the imperial response to agrarian rebellions.
Amid the gradual collapse of imperial authority, Yu and his family accompanied Emperor Yang in his retreat to Jiangdu.
After Emperor Yang was killed in a coup d'état led by the general Yuwen Huaji in 618, Yu and his sons were executed.
In the fall of 615, while Emperor Yang was touring the northern frontier of his empire, the Eastern Turkish (Tujue) leader Shibi Khan launched a surprise attack against Yanmen Commandery.
[d][5] Emperor Yang was frightened, but Yu suggested that he try to restore the morale by announcing publicly that he was terminating the campaigns against Goguryeo and would award the soldiers greatly if they could lift the siege.
Following his brother-in-law Xiao Yu's advice, however, the emperor also sought further help from Princess Yicheng, who sent her husband a false report of a northern attack on the khaganate.
With credit for his salvation murky, the emperor followed the advice of Su Wei and others to renege on most of his extravagant promises of reward; he also returned to Luoyang and began planning another expedition against Goguryeo, causing still more disaffection throughout the army.
In 616, because much of Sui territory had become engulfed in agrarian rebellions, Yu suggested that an army be stationed at Luokou Storage (洛口倉, near the eastern capital Luoyang) to protect it from pillagers, and Emperor Yang rebuked him for being fearful.
By spring 618, Emperor Yang, aware that rebels had occupied much of the northern empire, no longer had any intent to return to the north, wishing to take refuge at Danyang (丹楊, in modern Nanjing, Jiangsu), south of the Yangtze River.
Yu endorsed the plan, and despite opposition by the general Li Cai (李才), Emperor Yang began building a palace at Danyang in anticipation of moving the capital there.