head of a household; business owner; proudly independent person
Modern figurative use: someone who is the master of their own domain, whether a home, a small business, or a personal sphere, with a sense of proud independence.
Historical literal meaning: a lord who ruled a single castle and its domain. Now used mainly in historical contexts or as the origin of the modern figurative sense.
After retirement, he opened a small shop and lives freely as the master of his own little domain.
At home, he is the lord of his own castle.
In the Warring States period, ruling a domain as the lord of a single castle was a mark of a daimyo.
城主 refers specifically to the lord of a castle, while 一国一城の主 emphasizes the independence and authority over a whole domain, often used figuratively today.
マイホームパパ is a family-oriented dad, whereas 一国一城の主 implies a more assertive, independent mastery over one's household or business.
Literally 'lord of one country and one castle'. Originates from the feudal era when a daimyo held a single castle and its territory. The modern figurative sense extends this to anyone who is the undisputed master of their own small domain.