<論説>享保期の上方における幕府広域支配と大名預所 : 狭山藩の狭山池預所を事例に

Abstract

河内国狭山池を享保六年(一七二一) から預所とした狭山藩北条氏を取り上げ、治水の局面において、享保期の所領錯綜地域・上方における幕藩領主の支配形態を、大名預所と幕府広域支配との関係から検討した。一八世紀初頭に至る幕府の治水制度整備、そして、地域における狭山池治水の体制の動揺を契機として、狭山藩は池の水防強化を目的に掲げて狭山新宿の支配を願い出た。大坂町奉行所は、池の保全と狭山藩陣屋周辺の治安維持という観点から同藩の主張を支持した。また、幕府中央は、狭山藩の能力を利用した治水の強化と河川支配の政務負担軽減を企図したが、同時に河川支配の「公共的」性格を担保するため、狭山池全体を同藩の預所とした。狭山藩による狭山池支配は、同藩にとって陣屋・自領の存立維持を動機としたものであった。一方、幕府にとっては、小規模外様大名を組み込んだ河川支配域の再編と、個別領主が直面する水害という危機の解消を同時に目指した判断であった。

This article addresses the question of how the Sayama domain, under the rule of the Tokugawa shogunate in the Kamigata region, came to administer the Sayamaike reservoir at the beginning of the eighteenth century, despite it being customary at that time to place responsibility for managing rivers, lakes and reservoirs with administrators of the shogunate. This paper will also illuminate the structure of government, and the methods of flood control employed by the shogunate and domainal lords of the period. From the middle of the seventeenth to the early eighteenth century, the shogunate established a system for maintaining dikes on the banks of large rivers, such as the Yodo and Yamato. Under this system, the responsibility for funding maintenance and mobilizing workers in the Kamigata region fell to the shogunate, not the local domains. This did not, however, apply to smaller and medium-sized rivers, lakes and reservoirs, such as Sayamaike. The hiyakunin, those in charge of managing this reservoir and controlling its sluice gates, were Rot under the jurisdiction of the Sayama domain or the shogunate, but were instead subjects of the Kawagoe domain. As a result, they would not comply with orders from the Sayama domain, even if these orders were issued in the event of a flood as part of an attempt to defend the reservoir. When a flood did occur in 1716, this resulted in the hiyakunin failing to prevent a dike of the Sayamaike reservoir from bursting. To compound matters, since administrators of the shogunate were not responsible for maintaining Sayamaike under the system in place at the time, they did not fully cover the cost of repairs to the reservoir. In 1718, after the aforementioned flood, Hanamura Zensuke, a retainer of the Sayama domain, applied to the Osaka Machibugyo-sho, a department of river management in Kawachi province, to obtain jurisdiction over the hiyakunin in order to resolve the problem of flood control at Sayamaike. The official in charge of the department supported the request, arguing that granting the Sayama domain control over the hiyakunin would enhance the efficacy of the department's flood control, thus increasing the safety of areas surrounding Sayamaike. In the twelfth month of that same year, the head of the department of the Osaka Machibugyo ordered that in the event of a flood, the hiyakunin were obliged to obey commands issued by the Sayama domain, although the official did not go so far as to place the hiyakunin under permanent jurisdiction of the Sayama domain. In the following year, the Sayama domain petitioned the central authority of the shogunate in Edo for complete jurisdiction over the hiyakunin. They argued that personnel from the Sayama domain could be dispatched to Sayamaike more quickly, and so defend it from floods more effectively than those of the Kawagoe domain or the Osaka Machibugyo-sho, due to the relative proximity of their lord's residence to the reservoir. Another motivation for their petition for jurisdiction over Sayamaike was the domain's desire to adequately irrigate villages within its own territory, as well as those subject to other lords and to the shogunate. The hiyakunin and the villages in the area irrigated by Sayamaike that did not already fall under the jurisdiction of the Sayama domain were opposed to the request, as they stood to lose a fair share of control over their self-governance, as well as management of the reservoir and its water. In 1721, after surveying hiyakunin and the officials of these villages, the central shogunate authority granted the Sayama domain jurisdiction over the entire reservoir, hiyakunin and farmlands in the surrounding area, in place of the shogunate, with the stipulation that this did not constitute a transfer of territory from the shogunate to the domain. Exercising its newly acquired power, the Sayama domain established a new system of flood control at Sayamaike. It redefined the duties of the hiyakunin to obey the domain's orders, and institute a rule regarding the cost of repairs to the reservoir; it allocated taxes from the surrounding farmlands to the shogunate for the costs incurred. In 1723, the Sayama domain petitioned the central authority of the shogunate and the Osaka Machibugyo-sho for the right to patrol areas upstream from Sayamaike in order to prevent soil erosion into streams, despite the fact that the shogunate had put the Kishiwada domain in charge of inspecting and managing erosion in those areas thirty-four years earlier. The shogunate (eventually granted the Sayama domain oversight, under the jurisdiction of the Osaka Machibuyo-sho. The Sayama domain sought to control Sayamaike in order to serve its own interests, and to prevent disasters within its territory and in the vicinity of the lord's residence. For its part, the shogunate sought to involve the Sayama domain in the restructuring and management of rivers in the Kamigata region at that time, by granting it jurisdiction over the reservoir. In doing so, the shogunate also intended to help the domain with its efforts to avoid flood disasters within its own territory.