Founding king of Shang who overthrew the tyrant Jie by "revolution"
Cheng Tang is China’s first "revolutionary" — the "Tang" of the "Tang–Wu revolution." Jie, the last Xia ruler, was cruel and had lost the Way; Tang gathered strength from his base at Bo, defeated Jie at the Battle of Mingtiao, and founded the Shang. This change of dynasty established one of the most important propositions in Chinese political thought: the Mandate of Heaven is not eternal — when a ruler loses virtue, the Mandate can be transferred, and so overthrowing a tyrant is legitimate. This "Mandate–revolution" logic was inherited and systematized by the Zhou and became the standard justification for every later change of dynasty.
Tang saw a hunter set nets on all four sides, praying "let every creature of the world enter my net," and ordered three sides removed, leaving only one, changing the prayer to "let only those who defy their fate enter my net." The lords heard of it and said, "Tang’s virtue is complete." The story is less about mercy than about political signaling: before attacking Jie, Tang needed the world to believe that what he sought was not extermination but a new order.
A seven-year drought struck early Shang, and the diviner said a human sacrifice was needed. Tang said, "I pray for rain for the people; how can I kill a man? Let me be the offering." So he cut his hair and nails, wrapped himself in white cotton, and reproached himself for six faults before Heaven in the mulberry grove. Legend says that when he finished, heavy rain suddenly fell. A ruler offering himself as sacrifice to answer to Heaven — this prototype later evolved into the imperial tradition of the "edict of self-reproach."