Why was a lord’s journey such a big operation? Unpacking sankin-kōtai

What the sources say

Sankin-kōtai (“alternate attendance”) was a policy of the Tokugawa shogunate that required most daimyo to alternate between living in their domain and in Edo. It was made compulsory for tozama daimyo in 1635 and for fudai daimyo from 1642, and remained in force until 1862, apart from an eight-year period under Tokugawa Yoshimune.

The daimyo’s wife and heir were required to remain in Edo while he was away.

Why the journey was large

In principle the attendance was a military service to the shogun. Each daimyo was required to furnish a number of samurai according to the assessed yield of his domain, and these accompanied him on the journey.

The processions used the main highways, and special lodgings called honjin were available to daimyo on the way. The movement of so many people encouraged road building and the growth of inns and facilities along the routes.

The cost

Daimyo had to maintain residences in both places and pay for the journey. Estimates of the burden vary a lot: one account says such costs often made up 70 to 80 per cent of annual spending, while another gives about a quarter of budgets. Treat any single figure with care, since it differed by domain and period.

Interpretation

Historians connect the system to political control: constant surveillance, family in Edo, and a heavy financial load. It also had effects nobody planned, such as the roads and the cultural exchange between Edo and the provinces.