ruler's privy purse
Historical term referring to the personal treasury or private funds of a monarch or ruler. Rare in modern usage.
The privy purse was used as a personal financial resource for the emperor.
From 内 (inside, private) + 帑 (treasury, storehouse) + 金 (money). The exact historical derivation is uncertain; the term is a Sino-Japanese compound referring to the private funds of a ruler.