Hoshina Masaari

Who They Were

Hoshina Masaari (保科正益, ほしな まさあり) was a Japanese samurai and the last daimyo of the Iino Domain, a minor fief in Kazusa Province assessed at 20,000 koku. He was born in Edo on March 22, 1833, and died on January 23, 1888. His life spanned the closing decades of the Edo period (1603–1868) and the first two decades of the Meiji era that followed.

Masaari belonged to a branch of the Matsudaira family of Aizu. The founder of the Iino line, Hoshina Masasada, was the younger brother of Hoshina Masayuki, the first lord of Aizu. This connection gave the Iino lords a distinguished pedigree despite their modest domain. Masaari was the son of Hoshina Masamoto, the ninth lord of Iino, and was born in the family residence in Edo.

Life and Career

Masaari entered the world under unusual circumstances. He was born weak, and his father Masamoto did not notify the shogunate of the birth, as was required for samurai heirs. Masamoto's first and second sons died in quick succession, however, forcing him to report Masaari's existence to the shogunate in 1836. This delay is why some sources give 1836 as Masaari's birth year. He was formally made heir in 1847, and when his father died the following year, he succeeded to the headship of the Iino Domain.

In 1850, Masaari received the family's hereditary court title of Danjō no chū, a rank associated with the Board of Censors. Three years later, in 1853, he led Iino troops in the defense of Uraga Bay when Commodore Matthew C. Perry and the U.S. Navy's East India Squadron arrived. This was the first major test of Japan's coastal defenses in the face of Western pressure, and Masaari's participation placed him among the lords who confronted the crisis directly.

Within the Tokugawa administration, Masaari held a series of minor posts. His most significant appointment came in the second year of the Keiō era, when he became a wakadoshiyori, a junior councilor in the shogun's government. He also served as chief commander of the multi-domain military force sent against Chōshū during the Chōshū Expedition, leading troops on the Iwami front. This campaign was part of the shogunate's failed attempt to reassert control over the rebellious western domains.

After the Boshin War, the new imperial government ordered Masaari to investigate those deemed responsible for the conflict. It was in this capacity that former Aizu karo Kayano Gonbei was executed at Masaari's residence in Azabu in 1869. The karo was a senior retainer of the Aizu domain, and his execution marked a grim conclusion to the wartime loyalties that had divided the Hoshina family's two branches.

Why They Matter

Masaari's significance lies less in the size of his domain than in the positions he held during a period of national upheaval. As a wakadoshiyori and commander in the Chōshū Expedition, he was part of the shogunate's last generation of administrators, men who tried to hold the Tokugawa order together as it collapsed. His role in the defense of Uraga in 1853 placed him at the symbolic beginning of that collapse, when Perry's ships first forced Japan's isolationist policy open.

His post-war work investigating Boshin War responsibility shows how the Meiji government used former daimyo to legitimize its own consolidation of power. Masaari's involvement in Kayano Gonbei's execution linked him to the punitive measures that followed the war, even though his own domain had been on the shogunate's side. Like many former lords, he adapted to the new order, joining the kazoku nobility as a viscount (shishaku) in the Meiji era.

The Name in Japanese

The name is written 保科正益 in kanji.

• Kana reading: ほしな まさあり
• Romaji: Hoshina Masaari

The surname 保科 breaks down as follows:

• 保 (ほ, ho): "to protect" or "to preserve." This character carries the sense of safeguarding something, and appears in words like 保証 (ほしょう, guarantee).
• 科 (しな, shina): "department," "section," or "field." In this context it functions as part of the family name rather than carrying a standalone meaning, but its root sense is that of a category or division.

The given name 正益 breaks down as follows:

• 正 (まさ, masa): "correct," "right," or "proper." This is a common element in samurai names, conveying moral uprightness and legitimacy. It appears in words like 正義 (せいぎ, justice).
• 益 (あり, ari): "benefit," "profit," or "increase." The character suggests gain or advantage, and appears in compounds like 利益 (りえき, profit). When used in a name, it often carries the sense of flourishing or being of use.

The full name thus reads as something like "one who protects the proper benefit," though as with most Japanese names, the combination is more evocative than literal. The surname 保科 is shared by the Hoshina branch of the Matsudaira family, and the characters themselves predate Masaari by centuries.

Legacy

Masaari's eldest son, Hoshina Masaaki, succeeded him as head of the family. One of Masaari's daughters, Shizuko, married Iwasaki Hisaya, the younger brother of Iwasaki Yatarō, the founder of the Mitsubishi conglomerate. This marriage tied the old daimyo line to one of the most powerful industrial families of the Meiji era.

The Iino Domain itself did not survive the Meiji reforms. Like all domains, it was abolished in the early 1870s, and its territory was absorbed into the new prefectural system. Masaari's own transition from daimyo to viscount mirrored that of hundreds of former lords who traded feudal authority for noble titles under the new government. His career, from the defense of Uraga to the execution of Kayano Gonbei, traces the arc of a samurai class that served the shogunate, fought its wars, and then helped dismantle it.