He is documented as the fourth son of King Wen and brother of King Wu, later given the fief of Zhou near present day Qishan, Shaanxi, but no Zhou era or Han era source states where he was personally born, and the fief he is named for was granted only after the conquest of Shang.
What would resolve this A Western Zhou era inscription or record naming his birthplace, which no bronze inscription or transmitted text recovered so far supplies.
OpenEarly Chinese history; Western Zhou archaeology and epigraphyDivinity Atlas Open Questions Register, First Edition