Keian Incident

This incident occurred in July 1651 (Keian 4) when a rebellion planned by military scholar Yui Shosetsu was put down before it could begin. It is also known as the Keian Incident or the Yui Shosetsu Rebellion. Because no records from the shogunate have been handed down, the full story remains a mystery, but the gist of the plan was said to be: (1) the ringleader, Masayuki, would attack the treasure house at Kunozan in Suruga and then seize Sunpu Castle; (2) one of the gang, Marubashi Chuya, would set fire to various places in Edo, including the Enshogura saltpeter storehouse in Edo and Koishikawa, and poison the water supply. Taking advantage of the chaos in the city, he would then disguise himself as a member of the Kishu Tokugawa clan and infiltrate Edo Castle and seize it. (3) Members of the gang would also cause trouble in Kyoto and Osaka by setting fires and other means. Masayuki left Edo on July 22nd for Sunpu, but the plan was discovered the next day, Tadaya was arrested in Edo, and Masayuki and his party were surrounded by police from the Sunpu magistrate's office and committed suicide. The rest of the group were either captured in the Shogunate's net that was spread all over the country or committed suicide, and on August 10th, the group and 35 of their relatives were executed, bringing the matter to a close.

It is said that Masayuki recruited 2,000 ronin into his plan, but it was unrealistic for such a small number of people to take over a castle, and this led to the relationship between Masayuki and Tokugawa Yorinobu of the Kishu clan being talked about in later generations. As the son of Ieyasu, Yorinobu was eligible to become Shogun after Ietsuna, who had become Shogun at the age of 11 in April of that year, and he had a reputation for being anti-Shogunate in his words and actions. As for the purpose of the rebellion, a copy of Masayuki's suicide note was made by those involved in his capture and has been circulated. According to it, Masayuki followed the aspirations of Matsudaira Sadamasa, the previous lord of Kariya Castle in Mikawa, who had been punished for denouncing the Shogunate in July of the same year, and he stated that he intended to break the situation of "the lawlessness of the country and poverty of all classes." Because many of the participants were ronin, the current view is that Masayuki's purpose was to solve the problem of samurai ronin, which was estimated at 300,000 to 400,000 at the time. However, this estimate is exaggerated and difficult to support. What is certain, however, is that the plan was highly urban, with arson and poisoning of the water supply. From the beginning of the Tokugawa Shogunate, Edo was a place where many people, such as young retainers and middle-ranking officers who worked as traveling servants for samurai families, concentrated, and they created urban problems of being renegade. Especially during the Keian period, the discontent of the lower classes of Edo, who had lost employment opportunities due to the poverty of the samurai and the cessation of large-scale construction projects such as Edo Castle, was on the brink of explosion. These unemployed wanderers were also ronin in the terminology of the time, and it is thought that the later legend of Masayuki interpreted the problem of ronin as a problem of "long-established samurai ronin" in the narrow sense.

[Akira Takagi]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

1651年（慶安4）7月、軍学者由比正雪(ゆいしょうせつ)が企てた反乱が未然に鎮圧された事件。慶安の変、由比正雪の乱ともいう。幕府の記録が伝わっていないため全貌(ぜんぼう)は謎(なぞ)に包まれているが、計画の骨子は、(1)首魁(しゅかい)の正雪は駿河(するが)久能山(くのうざん)の金蔵を襲ったのちに駿府(すんぷ)城を奪取する(2)一味の丸橋忠弥(まるばしちゅうや)は江戸・小石川塩硝蔵(えんしょうぐら)など江戸各所に放火、また上水道に毒を投入し、市中の混乱に乗じて紀州徳川家と偽って江戸城に潜入し、これを奪取する(3)京都、大坂でも一味の者が放火などで騒動を起こす、というものであったと伝えられる。正雪は7月22日に江戸をたって駿府に向かったが、その翌日には計画は露顕し、忠弥は江戸で召し捕られ、正雪の一行は駿府町奉行(まちぶぎょう)の捕り手に宿を包囲されて自害した。そのほかの一味も全国に張られた幕府の網に捕縛され、あるいは自害し、8月10日、一味とその親族35人の処刑で一件は落着した。

　正雪が計画に引き入れた浪人は2000人と伝えられるが、この程度の人数で城を乗っ取るのは現実性に欠けており、そこに紀州家徳川頼宣(よりのぶ)と正雪との関係が後世に云々(うんぬん)される素地があった。家康の子である頼宣は、この年の4月に11歳で将軍となった家綱に次いで将軍となる資格があり、また反幕的言動でとかくの風評があったからである。次に反乱の目的については、正雪の遺書の写しが捕縛関係者によってつくられ、流布(るふ)している。それによれば正雪は、同じ7月に幕閣を糾弾して処罰された先の三河刈谷(かりや)城主松平定政(さだまさ)の志を継ぎ、「天下之制法無道にして上下困窮」という事態を打開する意図があったと述べている。これと参加者の多くが浪人であったことから、正雪の目的が、当時30万～40万と推計されている武士の浪人問題の解決にあったという見方が、現在の通説となっている。しかし、この推計は過大であり、支持しがたい。ただ確かなのは、この計画が放火、水道への毒投入など優れて都市型である点である。幕初から江戸には若党(わかとう)・中間(ちゅうげん)など武家の渡り奉公をする人口が集中し、彼らに特有の傾(かぶ)き者(もの)の都市問題が発生していた。なかんずく慶安のころは、旗本の困窮と江戸城など大型普請(ふしん)の途絶によって雇用の機会を奪われた江戸下層人口の不満は、一触即発の状態にあったと思われる。これらの雇用主のない渡り者も、当時の用語では浪人であったのであり、この浪人の問題が狭い意味での「歴々の武士の浪人」問題と受け取られたのが、後世の正雪伝承と考えられる。

［高木昭作］

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