How did the Zhou dynasty defeat and replace the Shang dynasty?

The transition from the Shang dynasty to the Zhou dynasty was a multi-generational process driven by the strategic expansion of the Zhou kingdom and the internal exhaustion of the Shang state.1

Under Wenwang, the Zhou became a formidable power, extending their influence and building alliances. The Shang, meanwhile, weakened their own position through extensive military campaigns against northern nomads and eastern tribes.1

The final conquest was led by Wuwang, who organized an invasion force consisting of Zhou troops, the Jiang, and eight allied western tribes. During the decisive battle, the Shang vanguard—likely remnants of previously suppressed eastern tribes—defected, causing the Shang army to collapse. Following the victory, the Zhou established the concept of Tianming (the Mandate of Heaven), which justified the overthrow of the Shang ruler, Dixin, by framing his rule as tyrannical and immoral.12

Consolidation required further effort; after Wuwang’s death, his brother Zhougong served as regent, suppressing a major rebellion by Shang loyalists and renegade Zhou princes to secure the new dynasty's control over China.1