What Are the Four Vaults (Mu Ku) in Ba Zi? Chen, Xu, Chou, Wei & Wealth Storage

Sitting at the final month of spring, summer, autumn, and winter, the four Earth branches—Chen, Wei, Xu, and Chou—gather the closing season's qi into storage before the next season begins.

Their storage roles are fixed: **Chen stores Water, Xu stores Fire (and Earth), Chou stores Metal, and Wei stores Wood**.

The exact same branch can behave as a dynamic warehouse (Ku) or a sleepy dormancy chamber (Mu):

When the stored element has roots, seasonal support, or vitality in the chart, it sits in a **Vault**—ready to pour out when a luck cycle unlocks the door.

When the stored element is weak, isolated, and lacking support, entering the branch reads as **Tomb**—manifesting as hesitation, bottled-up feelings, or talents kept under wraps.

Your Wealth Vault is the storage branch of the element your Day Master controls:

Jia / Yi Wood (controls Earth): **Xu** (and the four Earth branches as Earth reservoirs);

Bing / Ding Fire (controls Metal): **Chou** (Metal Vault);

Wu / Ji Earth (controls Water): **Chen** (Water Vault);

Geng / Xin Metal (controls Wood): **Wei** (Wood Vault);

Ren / Gui Water (controls Fire): **Xu** (Fire Vault).

Classical texts say 'A vault does not release its treasure until clashed' (Chen–Xu clash or Chou–Wei clash). When a strong Day Master meets a transit that clashes its Wealth or Officer Vault, dormant assets or career breakthroughs often surge into reality.

However, if the Day Master is weak or the vault is already broken in the natal chart, a heavy clash can instead trigger unexpected expenses, overextension, or burnout.

People with prominent Vault branches—especially in the Day or Hour pillar—tend to value security, long-term assets, and privacy around money.

The flip side is a tendency to bottle up emotions or replay old memories, which softens when you intentionally build open communication and steady cash-flow habits.