<論説>寛政改革期の蝦夷地政策

Abstract

従来、寛政改革期に積極的な蝦夷地政策の存在を認めないのが定説であったが、新出資料である松平定信自筆「蝦夷惣論」等により、当該期の蝦夷地政策の意義が解明できた。天明八年(一七八八) 、ロシアの動向を危機と見た老中松平定信と老中格本多忠籌とは、蝦夷地の軍備と開発を主眼とする幕府直轄策を唱えたが、ロシアに関心を持たない層は提案に反対した。代替案として、奥羽への奉行設置が決まるが、寛政元年(一七八九) のクナシリ・メナシの戦いの発生により、棚上げされる。この事件を契機に、蝦夷地へのロシアの介入をおそれた幕府は、蝦夷地の軍備とアイヌの帰服策の実施を松前藩に担わせ、幕府役人を派遣し松前藩を監視することとした。寛政四年のラクスマン来航を受け、幕府は、蝦夷地政策を管掌する奉行の奥羽への設置と南部・津軽の軍事動員に加え、幕府直轄交易所の蝦夷地への設置をも視野に入れ、目付の見分を実施した。こうして、寛政十一年の幕領化で実施される蝦夷地政策の要諦は出そろったのであり、寛政改革期は、幕領化の実現に向けた基盤が固められた時期と位置づけられる。

How can the policy of the Tokugawa bakufu toward Ezochi during the first part of the decade of 1790, which grew out of the positive policy of development from the decade of the 1780s, be located within the historical processes that concluded in the integration of eastern Ezochi into bakufu territory? The consensus of previous studies has seen Matsudaira Sadanobu, who was central to bakufu policy from the later half of the decade of the 1780s through the first half of the 1790s, as passive in regard to the problem of Ezochi and lacking any clear-cut policy for the region. In this article, I focus on the influence of Russia and make clear that the consensus is mistaken and that Sadanobu's Ezochi policy was ground breaking. In 1785 the Kamusasukafu sekko (Considerations of the land and customs of Kamchatka) of Kudo Heisuke drew the attention of the bakufu, which dispatched an exploratory party to observe Russian moves on Japan's northern frontier. Having grasped the state of Russian activities, the bakufu sent a second exploratory party in order to fashion a new policy, but it was frustrated by the collapse of the Tanuma Okitsugu regime. Matsudaira Sadanobu, who had become an Elder, roju, in 1787, recognized the importance of policy toward Russia and tried, along with Honda Tadakazu, to positively promote a policy toward the borderland between Russia that was Ezochi. However, because the very existence of Russia was not well known in Japan, there was little understanding of the necessity for an Ezochi policy, and it was extremely difficult to implement. At the time, the Matsumae domain was charged with Ezochi policy. The two men put an end to this arrangement and established an administrator, bugyo, in Ezochi; the bakufu planned to deal with the Ezochi problem directly on its own However, due to the strong resistance to any change in the system that had begun in the early Edo period, the two leaders maintained the existence of the Matsumae domain, and modified their plan, having a bugyo installed in Tohoku rather than in Ezochi. In the fifth month of 1789, just as this change in policy was being recognized, a number of Ainu attacked and killed several Japanese on Kunashiri and Nemuro. Because Russian involvement was suspected, the bakufu temporarily suspended the plan and dispatched an exploratory party to confirm the situation. It was soon discovered that there had been no Russian involvement, but as one Russian was found to be living on the island of Etorofu, the bakufu pressed the Matsumae domain to strictly enforce their Russian policy and sent an official party to oversee it. The official party dispatched in 1791 reported in greater detail on the advance of the Russians. Judging the situation serious, Honda Tadakazu again proposed implementation of the original plan to place a bugyo in Ezochi and have the bakufu deal with policy directly. The more cautious Matsudaira Sadanobu saw that resistance to that policy remained strong and pursued a course that kept the Matsumae domain intact, established the bugyo in Tohoku, and also had the bakufu keep an alert eye on Russian movements through the Matsumae domain. Debates within the bakufu were proceeding slowly, but shifted abruptly with the arrival of the Russian envoy Laxman in 1792. A proposal arose to establish a bakufu-run trading post in Ezochi while at the same time respecting conservative opinion on Ezochi, keeping the Matsumae domain and the bugyo in Tohoku. This was a groundbreaking proposal that overcame the binary thinking that required choosing the Matsumae domain or the bakufu and opened the way for the bakufu to deal directly with Ezochi policy and still maintain the Matsumae domain. Due to the arrival of Laxman, it was now obvious to one and all that Russia had its sights on Ezochi and Japan, and there was no longer any opposition to the plan. Then, in 1793, an exploratory party was dispatched to collect information to implement the new plan. In 1799 the bakufu divided Ezochi into two, creating a system under which the Matsumae domain would control the northwest and the bakafu the southeast portion of the territory. This system can be called an expansion of the conception of a bakufu-run trading post whose establishment had been projected to concern just a small portion of Ezochi under that plan adopted in 1793. The argument initiated by Matsudaira Sadanobu at the beginning of the 1790s became an opportunity to promote change in the bakufu's policy for Ezochi.