Tian Fu leads the second of the two star series that structure Zi Wei Dou Shu's fourteen major stars, an eight star group covering Tian Fu itself, Tai Yin, Tan Lang, Ju Men, Tian Xiang, Tian Liang, Qi Sha and Po Jun, whose palace positions across a birth chart's twelve palaces are fixed together as a set once Tian Fu's own position has been separately calculated from the birth data, a lookup structure mirroring the Zi Wei series' own six star mechanism but built around its own independent formula.
Ho Peng Yoke's study of Chinese mathematical astrology describes the pairing of a six star series and an eight star series, together making the fourteen major stars, as the structural foundation the whole chart is built on, every other calculation in the system, minor stars, transformations and the twelve palaces' own interactions, proceeding only once both series' positions are fixed for a given birth. The naming of Tian Fu's series after a storehouse rather than a court title, in contrast to Zi Wei's explicitly imperial series, reflects a broader pairing the tradition draws between rule and resource, a chart reading both what a native commands and what a native holds as related but genuinely distinct measures of a life's fortune.