The Tokugawa policy requiring daimyo to alternate residence between their domains and Edo was called sankin-kōtai. Under this system, feudal lords spent scheduled periods at the shogun’s court in Edo and maintained residences there even when they returned to their domains.
The policy developed from practices used by Tokugawa Ieyasu and his successors and was formally imposed on the tozama daimyo in 1635 by Tokugawa Iemitsu. Daimyo families commonly remained in Edo, effectively serving as hostages that discouraged rebellion. The costly travel and residence requirements also reduced the resources available for military opposition.
Sankin-kōtai had wider effects than political control. Regular processions connected provincial domains with Edo, stimulated road construction and commerce, and increased cultural exchange. It did not mean every lord traveled on exactly the same annual schedule; obligations varied according to status and circumstances. The policy was abolished during the Meiji Restoration in the 19th century.