Daimyo Shonin Seido (feudal lord pawn system) (大名証人制度)
Daimyo shonin seido was the system that the Edo bakufu (Japanese feudal government headed by a shogun) held hostages from feudal loads and their senior vassals and put them up in Edo.
The Edo bakufu held hostages from feudal lords and their senior vassals to stabilize their administration.
Wives and children of feudal lords were required to live in Edo and senior vassals such as Karo (chief retainer) put pawns (hostages) in Edo from their family members in turn.
As for senior vassals, this shonin seido was abolished on the recommendation of Masayuki HOSHINA in 1665.