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Aizu and the Boshin War: The Tragedy of the Byakkotai and Tsurugajo Castle
An examination of the Aizu domain's resistance in the Boshin War, traced through historic sites including Iimoriyama (Byakkotai) and the Sazaedo pagoda.
武
Author
Taketoki
| Samurai History
Contents
MOKUJI
一
Aizu Domain and Matsudaira Katamori: Political Context
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二
Iimoriyama and the Byakkotai
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三
Sazaedo: The Architectural Marvel
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四
Amidaji and Asaka Kuninomiyatsuko Jinja
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五
FAQ
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Aizu Domain and Matsudaira Katamori: Political Context
The Aizu domain was bound by the fifteen-article family code established by its first lord Hoshina Masayuki, declaring absolute loyalty to the Tokugawa shogunate as the domain’s fundamental duty. This code effectively predetermined the Aizu domain’s fate in the Bakumatsu period. In 1862 (Bunkyu 2), ninth domain lord Matsudaira Katamori was appointed Kyoto Protector. His forces successfully expelled Choshu forces from Kyoto in the Forbidden Gate Incident of 1864, but this deepened the antagonism with the Satsuma-Choshu alliance that would form the new Meiji government.
After the Restoration Decree of 1867 and the Battle of Toba-Fushimi in January 1868, the Aizu domain was designated an enemy of the court. The Boshin War expanded northward; in August 1868 new government forces entered Aizu territory. After approximately one month of siege, the Aizu domain surrendered on September 22.
Iimoriyama and the Byakkotai
Iimoriyama is a hill overlooking Aizuwakamatsu where members of the Byakkotai — a corps of sixteen-to-seventeen-year-old samurai recruits — committed mass suicide in August 1868, having mistaken fires in the castle town for the castle itself burning. One member (Iinuma Sadakichi) survived and left testimony that became a primary source for events. Over the subsequent Meiji, Taisho, and Showa eras, the Byakkotai became a symbol of loyal youth, especially emphasized in nationalist contexts during the Showa period. A commemorative stone donated by Fascist Italy in 1928 stands on the site, its political background worth noting.
Sazaedo: The Architectural Marvel
Sazaedo (Aizu), formally the Entsutsu Sansotodo, was built in 1796 (Kansei 8). The six-sided three-story wooden structure contains a double-helix internal passageway — ascending and descending visitors never cross paths. It functioned as a site for simulated pilgrimage to the thirty-three Kannon, and is designated an Important Cultural Property as a rare surviving wooden spiral structure.
Amidaji and Asaka Kuninomiyatsuko Jinja
Amidaji (Aizu) is the temple where fallen Aizu domain warriors were eventually interred. Lord Katamori is also buried in the precincts; he survived the war and died in 1893. Asaka Kuninomiyatsuko Jinja in Koriyama is an ancient shrine of Mutsu province whose environs saw fighting during the Boshin War.
FAQ
Was Matsudaira Katamori executed as an enemy of the court?
No. Katamori surrendered and was placed under house arrest, but was not executed. He subsequently served as chief priest of Nikko Toshogu and died in 1893 at age sixty-one.
Why did the Byakkotai mistake fires in the town for the castle burning?
The members apparently mistook fires elsewhere in the castle town for the castle keep itself. The castle in fact never fell by assault. The misidentification is attributed to limited visibility, smoke, and psychological distress.
What is the religious purpose of Sazaedo’s one-way design?
The design enabled large numbers of pilgrims to complete a circuit venerating the thirty-three Kannon images without congestion. It also embodied the concept of simulated pilgrimage, making the devotional practice accessible to those unable to travel.
Last updated: May 2026
さざえ堂（会津）, related to 会津・戊辰戦争
Wikimedia Commons / Public Domain
阿弥陀寺（会津）, related to 会津・戊辰戦争
Wikimedia Commons / Public Domain
安積国造神社, related to 会津・戊辰戦争
Wikimedia Commons / Public Domain
清水寺, related to 会津・戊辰戦争
Wikimedia Commons / Public Domain
延暦寺, related to 会津・戊辰戦争
Wikimedia Commons / Public Domain
── 了 ──
武
Author
Taketoki（たけとき）
Samurai History
Toku editorial team — samurai history. Insists on primary sources and castle-layout diagrams, walking battlefields from Yoritomo's Izu exile sites to the late-Edo battlegrounds.
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