was a Japanese warrior (samurai) who lived in the late Edo period. He was the 10th unit captain of the Shinsengumi, and died during the Boshin War.
Harada was born to a family of chà «gen, 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 Hà Âzà Âin-ryà « 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, the kanji for one, within a circle (). Later leaving the Matsuyama domain's service, he went to Edo, and trained at Kondà  Isami's Shieikan dà Âjà Â.
In 1863, Harada, together with Kondà  and others associated with the Shieikan, joined Kiyokawa Hachirà Â's Rà Âshigumi and departed for Kyoto. Shortly after reaching Kyoto, the Rà Âshigumi was disbanded and most of its members returned to Edo. Harada, Kondà Â, Serizawa Kamo and several others remained behind and formed the core of the group known as Mibu Rà Âshigumi, which later became the Shinsengumi.
Later, Harada became the Captain of the Shinsengumi tenth Unit. He was trained briefly under a dojo run by Tani Sanjà «rà Â, whom he introduced into the Shinsengumi. In 1865, Tani became the seventh Unit Captain. In Kyoto, Harada married a local woman named , and briefly had a private family residence near the Shinsengumi headquarters at Nishi-Honganji. The couple had a son, whom Harada named , taking the second character from the shà Âgun '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 Hikojirà Â's assassination, the Ikedaya incident, and the Sanjo Seisatsu incident.
Harada became a hatamoto, together with the rest of Shinsengumi, in June 1867. At one time he was accused (by former Shinsengumi member Ità  Kashitarà Â) as one of the assassins of the Sakamoto Ryà Âma and Nakaoka Shintarà  who were murdered on December 10, 1867. The truth behind the incident remains unclear, but according to the confession of the Tokugawa retainer Imai Nobuo later in 1870, the assassins were men of the Mimawarigumi (another Tokugawa-affiliated unit) under the hatamoto Sasaki Tadasaburà Â.
Later on December 13, 1867, he, Nagakura Shinpachi and several Shinsengumi members were involved in the ambush of Ità  Kashitarà Â's Goryà  Eji Kà Âdai-ji faction during the Aburanokà Âji incident.
In January 1868, Harada, together with the rest of the Shinsengumi, fought at the Battle of TobaâÂÂFushimi against the Imperial forces. He and his family subsequently left the Kyoto region for Edo. In March, the Shinsengumi was renamed to and advanced on Kai Province, and fought at the Battle of Kà Âshà «-Katsunuma, however, the unit was defeated and forced to retreat back to Edo. In the wake of this defeat, Harada and Nagakura Shinpachi left the Kà Âyà  Chinbutai after disagreements with Kondà  and Hijikata. According to Nagakura's version of events, Kondà  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 Shà Âgitai, 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 on July 6, 1868, 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 mounted 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.