Sankin kotai

• Japanese: 参勤交代 (sankin koutai)

Sankin kôtai, or "alternate attendance," was a system of military service which served as a central piece of the Tokugawa shogunate's systems for controlling the daimyô and maintaining power. Daimyô were obligated to alternate their residence between Edo and their domain; the expense of journeys to and from Edo each other year, with large entourages, combined with the expense of maintaining mansions in Edo often cost significant portions of the domain's resources, keeping them from consolidating power within their domains. The process of having so many samurai traveling to and from the capital, and maintaining residences in the capital, had a profound effect on cultural diffusion throughout the realm, and contributed significantly to the samurai-heavy demographic character of Edo.

Detail from a handscroll painting depicting the sankin kôtai procession of the lord of Iyo-Matsuyama han. Date unknown. National Museum of Japanese History

Initially voluntary, the system was made mandatory for tozama daimyô in 1635 in a re-issuance of the buke shohatto ("various laws for warrior families"); this was expanded to all daimyô in 1642. Lords were obligated to maintain a residence in Edo, where members of their close family would reside as hostages against the daimyô's disobedience or rebellion. As of 1648, each lord's heir was obligated to travel to Edo as well, alternating with his father, so that either the lord or his heir would be in Edo at any given time. Retired daimyô were also obliged to travel to Edo occasionally, to be re-confirmed in their being granted leave to remain in their domain (or in Edo, as they wished).

From 1684 onwards, the fudai daimyô had to make their sankin journeys every six months. Though most daimyô were obliged to perform this journey regularly, some tozama daimyô were granted exceptions, in most cases due to their great service to the realm in other respects, or after successfully arguing for the excessiveness of the burden. These included Tsushima han which governed relations and trade with Korea, and Fukuoka and Saga han, which contributed to the defense of the port of Nagasaki. Some northern domains which contributed to responses to Russian incursions also received temporary exemptions at times. Daimyô could also request, and be granted, exceptions from sankin kôtai on a one-time basis, when the lord was ill or the Edo mansion had burned down, or when the domain was fulfilling its obligations to the shogunate through corvée contributions to public works that year.

The sankin kôtai system ensured a reliable flow of considerable numbers of elite travelers across the country, contributing considerably to both official and private construction of post-stations and inns (and their surrounding towns), lighthouses and port facilities, maintenance of highways, and expansion of travel-related services, such as networks of messengers, porters, and horses. Corvée labor was employed to provide a considerable portion of the porters, boatmen, and the like. Barrier checkpoints called sekisho were established along the highways to regulate travel; among their functions, too, was to enforce that firearms not be carried into Edo (so as to help prevent rebellion), and that women (who might be hostage members of daimyô families) not be allowed to leave.

Many daimyô of western Japan also came to maintain mansions in Osaka and Kyoto as well, where the daimyô and his retinue would stay during their journeys to and from the shogun's capital, thus contributing to the culture and economy of these cities as well.

In the early Edo period, most daimyô of Kyushu, Shikoku, and western Honshû, traveled by ship to Osaka; sekibune were converted into luxurious gozabune for this portion of the journey, and riverboats were used to travel up the Yodo River from Osaka to Fushimi, from which the daimyô would then travel overland to Kyoto proper, and then along the Tôkaidô to Edo. Later on, however, many daimyô switched to traveling overland for as much of the journey as they could, avoiding sea travel. The Shimazu clan lords of Satsuma han likely had the longest journey; it typically took 40 to 60 days to travel the 440 ri to Edo. Though they originally sailed to Osaka from Kumisaki (Satsuma Sendai) or Wakimoto (Akune) on Kyushu's west coast, or from Hososhima in Hyûga province on Kyushu's east coast, they later switched to marching overland across Kyushu to Shimonoseki, and then walking the San'yôdô to Osaka.

The financial costs of sankin kôtai were among the heaviest burdens upon daimyô budgets, leading to many daimyô incurring very significant debts over the course of the period. Despite the expense, however, daimyô often felt obligated to maintain large entourages and lavish traveling conditions in order to maintain impressions of their power and prestige; not only the number of men in one's entourage, but the number of spears preceding and following the daimyô in procession, the number of certain types of baskets and baggage, among other elements of performance and display, meant a lot in terms of representing one's prestige and power to all those who could see it. For this reason, though the shogunate repeatedly tried to restrict the allowable size of sankin kôtai entourages, daimyô regularly exceeded the official limits. To give one example of the size and extent of the undertaking of sankin kôtai journeys, Tosa domain generally moved 1,500 to 3,000 people and their baggage each year between Tosa and Edo, a 500 mile journey over mountains, seas, and highway. In 1697, over 2,800 people accompanied the lord. Three years earlier, while the lord was resident in Edo, there were over 4,550 other Tosa people resident there with him. The domain had to pay porters, innkeepers, shippers, and food suppliers for the journey, and then also suppliers of food and other necessities (and luxuries) to this large Tosa population in the capital, as well as carpenters and artisans to service the domain mansion. In 1688, Tosa's total domain budget was 3,953 kan, of which 300 paid for the sankin kôtai journey, 1,422 paid for expenses related to the mansion in Edo, and 1,042 went to paying off loans from Osaka and Edo merchants. In total, in general, domains spent between 40% and 70% of their annual budgets on costs related to sankin kôtai.

In addition to simply being resident in Edo for a certain period of time, the performance of sankin kôtai involved formal audiences with the shogun, in which the daimyô would officially present himself to the shogun, as performance of military duty, in observance of feudal fealty to his lord. During a daimyô's time in Edo castle, only the daimyô himself and a certain number of higher-ranking retainers would actually enter the castle; the remainder of his retinue, some considerable number of middle- and low-ranking samurai, would remain outside the castle, sitting around on the ground, eating, drinking, chatting, sleeping, etc. Both when arriving in Edo, and when departing, the clan would send a formal request to the rôjû some six months ahead of time; the response would declare when they would be expected at the castle for formal audiences. Once actually arriving in the city, a message would be sent to announce their arrival, and either a member of the rôjû, or for lower-ranking daimyô a sôshaban, would come to the lord's mansion and deliver orders to venture up to the castle at a specific day and time to be received by the shogun; high-ranking daimyô would be received individually, while lower-ranking lords were received only in groups.

The sankin kôtai system came gradually to an end in the Bakumatsu period. Obligations were relaxed in 1862, leading to many daimyô abandoning their Edo mansions, or at least severely reducing the number of retainers they had stationed there. By some estimates, as many as 360,000 people left Edo in the 1860s to return to their home domains, representing too a severe decline in commercial demand for goods and services, and thus having a dramatic impact on the city's economy as well.