On When to Use and When to Drop Outer Structures (Wai Ge Yong She)

Outer Structures Are a Fallback, Not a Choice

If the useful god comes from the month, why do outer structures exist at all? Because sometimes the month offers nothing — day and month the same element, as in spring wood or winter water — and something must be taken by expediency. Shen is strict about the boundary: the moment the month has a usable god, or the stems already show wealth, officer or killings, the outer structure is out of the question. His sharpest point is that a broken useful god is not an empty month.