[Why] In late Cao Wei, imperial power waned and effective authority slid into the hands of general Cao Shuang, whose despotic arrogance crowded out the founding great clans represented by the Sima. [What] Sima Yi feigned illness to disarm Cao Shuang, then struck the moment Cao Shuang escorted the young emperor outside Luoyang for tomb-sweeping. He shut the city gates, deceived and executed Cao Shuang's three clans, and seized total military and political power over Cao Wei. [Who] Sima Yi was a long-patient strategist whose single decisive strike laid the foundation of the Jin state. Cao Shuang lacked decisive nerve and trusted promises naively, bringing destruction upon his entire clan. [How] The coup reduced the Cao Wei regime to a Sima dependency, transferring central power from the Cao imperial line to the Sima magnate clan. It became the milestone of clan-aristocratic power transfer in medieval China.
Why
The historic event of Gaoping Tomb Coup represents a key developmental peak of the Huaxia dynastic system. The critical turning point that shifted imperial power into noble clan oligarchy. By establishing this moral or administrative benchmark, it continues to shape the structural and philosophical fabric of ancient Chinese statecraft.