9 events the sources record for this year, grouped by region.
What happened
China (8)
In the eighth month, Zhou forces entered the Luo River and camped at Mangshan, pressing on Luo City; they burned the floating bridge with fire boats, and the Heqiao was cut. In the intercalary month, Gao Anuogong left Jinyang to defend and reached Heyang, but the Zhou forces fled at night. (Book of Northern Qi (Bei Qishu), Annals 北齊書 卷8)
Northern Zhou troops entered the Luo River, camped at Mangshan and pressed Luo City; they burned the floating bridge with fire boats, and the Heqiao was cut. (History of the Northern Dynasties (Beishi), Annals 北史 卷8 武平6年)
The emperor personally led six commanderies and took Heyin's great city of Northern Qi, but could not break the inner walls; he fell ill and withdrew in the ninth month. (History of the Northern Dynasties (Beishi), Annals 北史 卷10 建德4年)
Emperor Wu gathers the grand generals and above and sets out his plan for an eastern campaign against Qi; the officials agree (Book of Zhou (Zhoushu), Imperial Annals 周書 卷6 建德4年7月)
Emperor Wu takes the great city of Heyin with 60,000 men but cannot break the inner citadel; he falls ill and withdraws at night in the ninth month. Yuwen Xian and others take over 30 cities but abandon them and return (second campaign) (Book of Zhou (Zhoushu), Imperial Annals 周書 卷6 建德4年8月)