Assassination of Sakamoto Ryōma: Shinsengumi Suspected

[Note: Sakamoto Ryōma—whose life I chronicled in Ryoma: Life of a Renaissance Samurai—was assassinated in Kyoto near the end of 1867, at the pivotal moment when the Tokugawa regime was collapsing. Ryōma’s assassination is the subject of Part III of Samurai Assassins.]

[Imai Nobuo — Kyoto Mimawarigumi samurai who confessed involvement in the 1867 assassination of Sakamoto Ryōma]

Imai Nobuo — Kyoto Mimawarigumi samurai who confessed involvement in the 1867 assassination of Sakamoto RyōmaDuring the years that the Shinsengumi were arresting and killing anti-Bakufu rebels on the streets and alleys of Kyoto, another Bakufu security force called Kyoto Mimawarigumi (Kyoto Patrol Corps) were doing the same thing. While the Shinsengumi corpsmen, from Commander Kondō Isami and Vice-commander Hijikata Toshizō on down, were rōnin, the Kyoto Patrol Corps generally consisted of direct vassals of the shogun. When a band of Mimawarigumi swordsmen, including Imai Nobuo, assassinated Sakamoto Ryōma and his cohort Nakaoka Shintarō at the former’s hideout in Kyoto around the end of 1867, the Shinsengumi were suspected. In 1870, Imai confessed to the authorities that he and others had acted under orders from their commander, Sasaki Tadasaburō, who was also involved. But Imai claimed that he had not had a hand in the actual killings, since he and two others had been downstairs guarding the place while the others went upstairs, where they attacked Ryōma and Nakaoka. Ryōma’s assassination is the subject of Part III of Samurai Assassins.

Imai’s confession notwithstanding, for decades it was “generally believed that Sakamoto Ryōma and Nakaoka Shintarō were killed by Kondō Isami and Hijikata Toshizō,” he said in 1900 in an interview for an article titled “Sakamoto Ryōma Satsugaisha” (“Sakamoto Ryōma’s Killers”). “But actually I did it.” As I wrote in Samurai Assassins,  

Shinsengumi corpsman Shimada Kai denied that the Shinsengumi had anything to do with the assassinations, saying that they did not hear about the incident until the next day. Shimada’s claim is supported by another former Shinsengumi corpsman, Yūki Minizō. “We were at Kondō’s place that night,” Yūki recalled years later. “. . . When we heard about the assassinations the next day, we said to one another that whoever did it must have been a very skilled swordsman. . . . When we heard that it was Imai who had done it, it made sense. Imai was well known in Edo at that time for his great skill with a short sword. When he was set to attack, it was said that all you could see was his sword. Imai was the only person who could have done such work in such cramped quarters in so short a time.”

For on the assassination of Ryōma and Nakaoka, see An Indispensable Document for Knowing the Facts Regarding Ryōma’s Assassination.

The conflicting accounts of Ryōma’s assassination remain one of the enduring mysteries of the Bakumatsu era. I explore these events in detail in my forthcoming book, Samurai Swordsmen: The Definitive History of the Shinsengumi (1863–1869). For details see the Shinsengumi Hub.


Samurai Swordsmen: The Definitive History of the Shinsengumi (Helion, 2026) is now in production.
For professional guidance on Bakumatsu–Meiji Restoration history, see Historical Consulting.
Explore my books at Books at a Glance.

On “Renaissance Samurai” and a Curious Lack of Online Credit

If you’ve spent any time diving into Bakumatsu history, you’ve probably come across the phrase “Renaissance Samurai.” It’s a neat way to capture the fierce, transformative spirit of figures like Sakamoto Ryōma—a samurai not bound by the old codes but reborn into a rapidly changing world (and a true “Renaissance man” at that).

I coined the phrase in my book Ryoma: Life of a Renaissance Samurai to highlight exactly that—a multi-talented samurai caught between tradition and modernity, blazing a new path.

Lately, I’ve noticed the phrase popping up here and there online, often without a byline or a nod to its origin. Is this plagiarism? Probably not—more like a gentle reminder of the lower end of human nature.

But here’s the thing: words, ideas, and phrases don’t float in a vacuum. They come wrapped in stories, research, and countless hours of writing. When people use a phrase like “Renaissance Samurai” without credit, they’re missing the context, the depth, and the passion behind it.

So, if anyone likes the phrase, that’s great—because it means the story is still alive and resonant. But a little credit would be appropriate, I think—a respectful nod that keeps our collective storytelling honest and vibrant.

To everyone who’s read, shared, or been inspired by Ryoma: Life of a Renaissance Samurai, thank you. Your engagement keeps this history breathing—and “Renaissance Samurai” more than just a catchy phrase.

And to the rest of the internet: maybe next time, dig a little deeper before borrowing. We storytellers work hard to keep history alive—and honest.


Samurai Swordsmen: The Definitive History of the Shinsengumi (Helion, 2026) is now in production.
For professional guidance on Bakumatsu–Meiji Restoration history, see Historical Consulting.
Explore my books at Books at a Glance.

Matsudaira Katamori: Master of the Shinsengumi

Aizu samurai Yamakawa Hiroshi’s Kyōto Shugoshoku Shimatsu, a history of the office of the protector of Kyoto, was published in 1911. The office of the protector of Kyoto, which lasted for more than five years (1862 – 1867), was held by Matsudaira Katamori, daimyo of Aizu. As the protector of Kyoto, he was the master of the Shinsengumi.

Yamakawa served as a senior retainer to Katamori during the latter’s tenure in Kyoto. His book is a key source for my forthcoming Samurai Swordsmen: The Definitive History of the Shinsengumi amid the Fall of the Tokugawa Bakufu.



For professional guidance on Bakumatsu–Meiji Restoration history, see Historical Consulting.
Explore my books at Books at a Glance.

Who Was Serizawa Kamo?

There is not a lot of historically verifiable information about Serizawa Kamo, co-commander and co-founder of the Shinsengumi along with Kondo Isami. According to one contemporary from Aizu, Serizawa “was extremely courageous, but since he was violent, if one of his subordinates did something to displease him, he would beat him nearly to death.” 

I explore the enigma that is Serizawa Kamo in my forthcoming Samurai Swordsmen: The Definitive History of the Shinsengumi amid the Fall of the Tokugawa Bakufu.

(This photo of Serizawa’s grave at Mibu Temple in Kyoto, shared with that of his cohort Hirayama Goro, was taken on October 11, 2016.)


Samurai Swordsmen: The Definitive History of the Shinsengumi (Helion, 2026) is now in production.
For professional guidance on Bakumatsu–Meiji Restoration history, see Historical Consulting.
Explore my books at Books at a Glance.

 

The Samurai, the Ship, and the Golden Gate

Katsu Kaishu’s portrait by US Navy sailor Edward Kern
On St. Patrick’s Day, 1860, the first Japanese warship to reach North America entered San Francisco Bay—a moment noted in the local Daily Alta California on March 18:

“His Imperial Japanese Majesty’s war steamer Candinmarru, commanded by Kat-sin-tarroh, a Captain in the Japanese Navy, arrived in our harbor yesterday, and anchored off Vallejo street wharf, at three o’clock P.M., after 37 days’ passage from Uragawa. . . .”

The Daily Alta, of course, was referring to the arrival of the Japanese warship Kanrin Maru, captained by Katsu Kaishū, the “shogun’s last samurai” of my book Samurai Revolution. The American journalists really had no way to know the correct transliteration of the Japanese names, probably because at that early date there was still no standardization thereofand they certainly bastardized the pronunciation (Katsu Kaishū was his pseudonym; his given name was Katsu Rintarō).

Following is an excerpt from the book (without footnotes):

At dawn of the thirty-eighth day at sea, Katsu Kaishū caught his first sight of the North American continent—and one can only imagine the intense interest with which he took up his binoculars to view through dense fog the coastal mountains in the distance, “like great waves rising above the clouds,” he wrote in a journal-like account of his San Francisco experience in History of the Navy. The captain would have been standing on the deck of his warship—a white banner emblazoned with the red rising sun flying at the mainmast; at the mizzenmast a signal flag of red and white displaying [Admiral] Kimura’s family crest of an encircled diamond. As the Kanrin passed safely through the strait called the Golden Gate, into San Francisco Bay, Kaishū paid special attention to the forts on the north and south shores, for the state-of-the-art military technology naturally concerned the military scientist who would construct modern batteries on the coast of his own country. To this purpose, during his sojourn in and around San Francisco he kept meticulous notes. The battery at Fort Point, on the south shore, he wrote,”is equipped with tens of large guns. The battery is made entirely of brick, with loopholes at three levels. The flat upper surface, sixty or seventy ken [around 109 or 127 meters] in length and of a suitable width, is large enough to mount smaller guns. From the outside there appears to be plenty of room for posting sentries at the rear. On the hillside on the left [north] shore are lights for targeting vessels entering and leaving the bay.”

From the topography of the city, “with mountains on all four sides,” Kaishū was struck by “its similarity to our Nagasaki.” Presently, a tugboat approached. “Two of its men boarded our ship. . . . We requested them to lead us [further] into the bay.” “They were going to salute us with cannon fire from land,” wrote Fukuzawa Yukichi, who sailed on the Kanrin as a steward to Kimura. “If they were going to salute us, then we had to return the honor.” But the captain hesitated on the grounds that his tiny ship might not withstand the shock. Meanwhile, Senior Officer Sasakura Kiritarō was eager to return the salute. “No,” said the captain. “Rather than attempting to return the salute and failing, it would be better to let the matter alone.” But Sasakura was determined. “I can do it,” he said. “I’ll show you.” “Don’t be stupid,” the captain retorted. “There’s no way you can do it. But if you try and succeed, you can have my head.” Permission granted, Sasakura ordered some of the men to clean the guns and prepare the gunpowder. He returned the salute superbly, as Kaishū probably expected, assisted by Junior Officer Akamatsu Daizaburō, who used an hourglass to time the intervals between shots. Then Sasakura got his feathers fluffed up and strutted right up to his captain. “Your head belongs to me,” he announced for all to hear. “But I think you’d better keep it where it is for a while. I’m sure you’ll be needing it during the rest of our voyage.” Sasakura’s remark drew laughter from the entire company.

[Katsu Kaishū, portrait by U.S. Navy sailor Edward Kern (1860)]

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Katsu Kaishū is the “shogun’s last samurai” of Samurai Revolution, the only biography in English.