Sankin-kotai

Sankin kotai (参勤交代: sankin kōtai) was the requirement for all daimyo to leave their wives, and heirs at court in Edo as hostages. The daimyo were personally required to attend the shogun's court where they resided in alternate years. This in turn involved daimyo in the maintenance of a lavish lifestyle in Edo in addition to any residences or incomes spent in their home domains. For most daimyo, it took nearly half their income leaving them with little money to build resistance to the Tokugawa Shogunate.