Harada was born to a family of chūgen, or low-ranking quasi-samurai, who served the retainers of the Iyo-Matsuyama Domain (now the city of Matsuyama). He trained in the spear technique of the Hozoin-ryu style, and usually used that weapon in battle instead of a sword. During his time in Matsuyama, he was once ridiculed by a Matsuyama retainer as being a peon who was unfamiliar with how to properly commit seppuku. Harada, wishing to prove the man wrong, immediately drew his sword and attempted to commit seppuku; however, the wound was shallow, and he survived. Harada later boasted of his scar to his fellow Shinsengumi men, and the incident of his near-disembowelment is said to be the origin of the family crest he chose, which depicted a horizontal line within a circle (maru ni ichimonji (丸に一文字?)). Later leaving the Matsuyama domain's service, he went to Edo, and trained at Kondō Isami's Shieikan dōjō.
In 1863, Harada, together with Kondō and others associated with the Shieikan, joined Kiyokawa Hachirō's Roushigumi. Shortly after, Kondō and Serizawa Kamo separated from the Roushigumi, and formed the core of the group which later became the Shinsengumi.
Later, Harada became the tenth Unit Captain of the Shinsengumi. He trained briefly under a dojo run by Tani Sanjūrō, whom he introduced into the Shinsengumi. In 1865, Tani became the seventh Unit Captain. In Kyoto, Harada married a local woman named Masa, and briefly had a private family residence near the Shinsengumi headquarters at Nishi-Honganji. The couple had a son, whom Harada named Shigeru (茂?), taking the second character from the shogun Iemochi (家茂?)'s name. Harada was very trusted by vice-commander Hijikata. He was involved in many of the crucial missions the group faced and was very likely involved in the Serizawa Kamo (original commander of the Shinsengumi) assassination. He was involved in the Uchiyama Hikojirō assassination, the Ikedaya Affair, and the elimination of Itō Kashitarō's Kōdaiji faction. Harada became a hatamoto, together with the rest of Shinsengumi, in 1867.
At one time he was accused (by former Shinsengumi officer Itō Kashitarō) as the assassin of the famous Sakamoto Ryōma. The truth behind the incident remains unclear, but according to the confession of the Tokugawa retainer Imai Nobuo, Ryōma's assassins were men of the Mimawarigumi (another Tokugawa-affiliated unit) under the hatamoto Sasaki Tadasaburō.
Harada, together with the rest of the Shinsengumi, fought at the Battle of Toba-Fushimi. He and his family subsequently left the Kyoto region for Edo. He joined Shinsengumi's advance on Kai Province, and fought at the Battle of Kōshū-Katsunuma; however, the unit was defeated and forced to retreat. In the wake of this defeat, Harada and Nagakura left the old Shinsengumi, after disagreements with Kondō and Hijikata. According to Nagakura's version of events, Kondō wanted the surviving men to become his retainers; Nagakura, Harada, and a few others staunchly refused. Nagakura and Harada, taking with them some other Shinsengumi members, joined with a group of former Tokugawa retainers to form a new unit, the Seiheitai. Seiheitai left Edo shortly after Edo Castle's surrender, and headed north, hoping to take part in the fighting that was moving northward, toward Aizu.
After Seiheitai's departure from Edo, Harada, wishing to be with his wife and child, returned to the city. However, he was unable to leave the city, and so he joined the Shōgitai, which also sided with the Tokugawa regime. Harada fought at the Battle of Ueno, where he was severely wounded by enemy gunfire. Two days later, he died of his wounds, while at the residence of the hatamoto, Jinbo Yamashiro-no-kami.
There is a rumor that Harada did not die in 1868, but he survived and travelled to China and became a leader for a group of horse-riding bandits. There were reports that an old Japanese man came to the aid of the Imperial Japanese Army in the First Sino-Japanese War, and claimed to be Harada Sanosuke. This was reported in a newspaper in 1965, but remains unsubstantiated.
Harada in Fiction
Harada Sanosuke appears in Shiba Ryoutarou's novels Moeyo Ken and Shinsengumi Keppuroku.
In addition, Harada appears in the anime series Peacemaker Kurogane, as well as in the manga it was originally based on, Shinsengumi Imon PEACE MAKER and Peacemaker Kurogane. He is also featured in Kaze Hikaru (manga), Hakodate Youjin Buraichou Himegami (manga), Getsumei Seiki (manga) and Bakumatsu Renka Shinsengumi (video game series.)
Harada Sanosuke appears in anime series Hakuouki Shinsengumi Kitan.
- Ōishi, p. 29; Nakami, p. 51.
- Nakami, p. 51.
- Nakami, p. 51; Ōishi, p. 30.
- Ōishi, p. 160.
- Nakami, p. 186.
- Kusunoki, p. 92.
- Nakami, p. 52.
- Ōishi, p. 200
- Kikuchi, p. 228.
- Kikuchi, p. 229.
- Kikuchi, p. 230
- Nakami, p. 52. The term in Japanese is bazoku (馬賊?), literally, "horse-bandits".
- Watsuki, Nobuhiro (2003). "The Secret Life of Characters (6) Sagara Sanosuke". Rurouni Kenshin, Volume 2. Viz Media. p. 48. ISBN 1-59116-249-1.
- --- (1978). Shinsengumi Encyclopedia. Tokyo: Shin Jinbutsu Oraisha.
- Kikuchi, Akira (2000). Shinsengumi 101 no nazo. Tokyo: Shin Jinbutsu Oraisha.
- Kusunoki, Sei'ichirō (1992). Nihonshi omoshiro suiri: nazo no satsujin jiken wo oe. Tokyo: Futami Bunko.
- Nakami, Toshio (2003). Shinsengumi no koto ga omoshiroi hodo wakaru hon. Tokyo: Chūkeishuppan.
- Ōishi, Manabu. (2004). Shinsengumi: saigo no bushi no jitsuzō. Tokyo: Chūōkōron-shinsha.
- Yamamura, Tatsuya (1998). Shinsengumi Kenkyaku-Den. Tokyo: PHP Interface. ISBN 4-569-60176-6