Liu School (劉派)
Liu Jiangdong (劉江東) was another important disciple of Yang Yunsong. According to tradition, Yang Gong on his deathbed transmitted the secret Xie Zi Fa (些子法) method exclusively to Liu Jiangdong — a cryptic compass calculation system not shared with other students.
The Xie Zi Fa Mystery
The term '些子' (xie zi) has been the subject of centuries of debate. Some scholars interpret it as a specific mathematical formula encoded in the classical texts; others see it as a general reference to the 'small details' (些子 literally meaning 'a little bit') that distinguish expert practice from ordinary assessment. The deliberately obscure language of the Tian Yu Jing, which Liu's lineage preserved, has fuelled this ongoing scholarly debate.
Li Qi Emphasis
Unlike the Zeng School's emphasis on Form (landform observation), the Liu School leans more heavily toward Li Qi (理氣, compass calculation). This makes the Liu School a bridge between Yang Gong's original teachings and the later San Yuan/Xuan Kong developments.