6 events the sources record for this year, grouped by region.
What happened
China (6)
He mobilized more than a million men and women of Hebei to dig the Yongji Canal, linking the Qin River to the Yellow River and reaching north to Zhuojun. (History of the Northern Dynasties (Beishi), Annals 北史 卷12 大業4年)
Over a million men and women of Hebei were conscripted to dig the Yongji Canal, from the Qinshui River south to the Yellow River and north to Zhuo Commandery. (Book of Sui (Suishu), Imperial Annals 隋書 卷003 帝紀 大業4年1月)
Yuwen Shu, Grand General of the Left Wing Guard, defeated the Tuyuhun at Mantou and Chishui. (Book of Sui (Suishu), Imperial Annals 隋書 卷003 帝紀 大業4年7月)
In 608, when Yuwen Shu reaches Linqiang city, the Tuyuhun flee west in fear; Shu pursues, takes the two cities Mantou and Chishui, beheads more than 3,000, and captures 200 people from princes downward and 4,000 men and women. (Zizhi Tongjian (Comprehensive Mirror) 권181 608년 항)