In the Romance of the Three Kingdoms, there was a story with the word "three": During the Three Kingdoms period, Zhuge Liang, the prime minister of Shu Han, proposed strategies such as the "Wolonggang Advisor","Empty City Strategy" and "Burning Red Cliff" to save the country, which finally helped Shu Han win. The "Empty City Stratagem" was the story of Zhuge Liang's appearance in the Empty City.