When the Southern Song Dynasty was about to fall, the storyteller Chen Wuyong came up with a "knowledge payment system" after a fall in a ruined temple.
Others relied on swords and guns to fight against Mongolia, but he relied on giving online lessons to modern people eight hundred years later - "A Guide to Surviving in the Wilderness in Troubled Times".
The "homework" handed in by the students has become the sharpest weapon in his hand.
Until he came across the live broadcast room of a Mongolian lecturer on the platform: "Sweeping across Eurasia: Analysis of actual cavalry tactics".
The most intense KPI showdown across time and space in history.
