Oishi Yoshio (April 24, 1659 – March 20, 1703) served as the chamberlain of the Ako Domain in Harima Province, now part of modern-day Hyogo Prefecture, from 1679 to 1701. He is best known as the leader of the Forty-seven Rōnin in their 1703 vendetta and is honored as the central figure in the legendary tale of Chūshingura.
Oishi served as the head chamberlain (hittogaro) to daimyo Asano Naganori, overseeing the daily management of Ako Castle and directing the activities of its samurai. Under the Tokugawa system of alternate attendance (sankin-kotai), which required daimyo to spend every other year in Edo (modern-day Tokyo), the chamberlain essentially governed the domain in the lord’s absence. Appointed at a young age, Oishi was said to have earned Asano’s complete trust.
When Asano was ordered to commit seppuku for attacking Kira Yoshinaka in Edo Castle, the Tokugawa shogunate dissolved the Asano house. Oishi, who was in Ako at the time, managed the domain’s affairs and convinced the remaining samurai to surrender the castle peacefully to the shogunate’s representatives. His dignified and calm leadership left many wondering what he would do next, as he was widely respected as a capable and honorable man.
Initially, Oishi sought permission to restore the Asano family, but his efforts were unsuccessful. He then began planning a secret vendetta against Kira. To deflect suspicion, he deliberately appeared to abandon his sense of duty—frequenting geisha houses in Kyoto and behaving as though he had given up. This deceptive strategy was known as hiru andon ("daylight lantern")—something that appears useless but hides a purpose. Behind the scenes, he was coordinating with the remaining loyal Ako samurai.
Nearly two years later, on the 14th day of the 12th month in 1703 (according to the old Japanese calendar), Oishi and 46 fellow ronin launched a coordinated assault on Kira’s mansion in Edo’s Honjo district. They successfully killed and beheaded Kira. After the mission, Oishi sent Terasaka Kichiemon to inform Asano’s widow, Yozeiin, of their vengeance. The remaining 46 rōnin then proceeded to Sengaku-ji Temple in Shinagawa, where Asano was laid to rest, and voluntarily turned themselves in to the authorities.
Oishi and his fellow ronin were sentenced to seppuku—a punishment considered honorable compared to execution. They all accepted the sentence with dignity.
In death, Oishi became a symbol of the ideal samurai—loyal, strategic, and honorable. His ultimate goal of restoring the Asano clan was partly realized when the Tokugawa shogunate returned a portion (about one-tenth) of their former lands to the family.
In the famous kabuki play Kanadehon Chushingura, Oishi Kuranosuke is portrayed under the name Oboshi Yuranosuke. He also served as a prototype for one of the main characters in the Hollywood movie 47 Ronin.
See also
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Okudaira Sadamasa
Sadamasa was the son of Okudaira Sadayoshi and took part in several battles under Tokugawa Ieyasu, distinguishing himself in the Battle of Anegawa in 1570, where he took two heads. Around 1572 he was forced to enter the service of the Takeda clan, but after the death of Takeda Shingen in 1573 he returned to Tokugawa, leaving Tsukude Castle together with his men. As a result of this defection, Takeda Katsuyori ordered the execution of Sadamasa’s wife and brother, who were being held as hostages.
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Okubo Tadatika
Tadatika, the son of Okubo Tadayō, entered the service of Tokugawa Ieyasu at the age of eleven, and took his first head in battle when he was sixteen. After the establishment of the Tokugawa shogunate, he was appointed as a rōjū — a senior bakufu official — and was regarded as one of Ieyasu’s most trusted advisors, alongside Honda Masanobu. He is also known for his military chronicle Mikawa Monogatari, which describes Ieyasu’s rise to power and the early years of the Tokugawa shogunate.
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Okubo Nagayasu
Nagayasu was the second son of Okura Nobuyasu, a sarugaku theater actor from the Takeda clan. Takeda Shingen recognized the young man’s potential and took him into service, appointing him as a vassal to his general, Tsuchiya Masatsugu. During this period, Nagayasu changed his family name to Tsuchiya. He was entrusted with developing the Takeda clan’s gold mines as well as handling matters related to taxation.
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Nitta Yoshisada
Nitta Yoshisada was a loyal soldier of Emperor Go-Daigo, who in the 1330s attempted to restore direct imperial rule in Japan. The Nitta family was related to the Ashikaga house and was older in lineage. However, they did not join Minamoto Yoritomo at the start of his war with the Taira, as the Ashikaga did, and therefore did not receive high positions in the Kamakura shogunate. This may have been one of the reasons why Yoshisada rose against the Hōjō clan in 1333.
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Natsume Yoshinobu
Yoshinobu, a long-time vassal of the Matsudaira and Tokugawa clans, governed Hamamatsu Castle on behalf of the Tokugawa house. During the clashes between the Imagawa, Takeda, and Matsudaira clans, he served in the garrison of Nagasawa Castle and in 1562 took part in raids under the command of Itakura Shigezane. When, in 1563, a revolt of the Sōtō-shū sect followers broke out in Mikawa Province, Yoshinobu joined the rebels together with Honda Masanobu and Hachiya Sadatsugu.
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Nambu Nobunao
The Nambu clan was an ancient and powerful family that traced its lineage back to the Minamoto shoguns and had controlled a significant part of the Tohoku region in northern Honshu since the 12th century. Nobunao was born in Ikatai Castle, located in what is now the city of Iwate. He was the second son of Ishikawa (Nambu) Takanobu, the 22nd head of the Nambu clan. In 1565, Nobunao’s uncle, Nambu Harumasa, adopted him, brought him to Sannohe Castle, and named him his heir, later giving his daughter in marriage to him.
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Naito Ienaga
Ienaga was the son of Naitō Kiyonaga and served Tokugawa Ieyasu from an early age. Like his father, he was exceptionally brave, and thanks to his remarkable skill with the bow, he earned the nickname “the unrivaled archer.” Although both the elder and the younger Naitō belonged to the Jōdo Shinshū (“True Pure Land”) sect, during the Ikkō-ikki uprising in Mikawa Province in 1565, Ienaga did not support his fellow believers and instead sided with Tokugawa Ieyasu, earning his special trust. He later took part in the battles of Mikatagahara, Nagashino, and many other engagements while accompanying Ieyasu.
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Minamoto no Yoshitsune
Minamoto no Yoshitsune was the son of Minamoto no Yoshitomo and his second wife, Tokiwa Gozen, as well as the younger half-brother of Minamoto no Yoritomo, the founder of the first shogunate, who had once suffered defeat in the struggle against the Taira clan. Yoshitsune spent his childhood in exile at the Kuramayama Temple. According to legend, he studied not so much Buddhist sutras there as the arts of war. At the age of fifteen, he entered the service of the governor in Mutsu, Fujiwara Hidehira.
