Is “At Dingjun Mountain, he devised the plan to slay Xiahou Yuan” true?
attested in history
According to Records of the Three Kingdoms, Book of Shu, Biography of Fa Zheng, Fa Zheng suggested a surprise attack on Xiahou Yuan, and Huang Zhong, taking advantage of the high ground, shouted and killed him. Cao Cao lamented, 'Why did I not get Fa Zheng?'
Fa Zheng
A key minister of Shu Han, credited with ingenious strategies and the primary credit for the Battle of Hanzhong in official history.