Gensai Kawakami (河上 彦斎), born Komori Genjiro (Kumamoto, December 4, 1834 - January 13, 1871) was a Japanese revolutionary, one of the four great hitokiri (幕末四大人斬り "man-killers") who at the end of the Bakumatsu period,
around the middle of the 19th century, fought against the Tokugawa shogunate, which had ruled the country since 1603, leading to its downfall and the beginning of the Meiji era.
It is said that he was very calm and calculating, showing an incredible coldness in moments of crisis and tension. Physically he had delicate features and long hair, and it is said that at a distance he could be mistaken for a woman or a child.
The son of Komori Sadasuke, a vassal of the daimyō of Kumamoto, his brother Hanzaemon was chosen as the heir of the family, so at the age of 11 he was given up for adoption to Kawakami Genbei (河上彦兵衛), another vassal of Kumamoto.
Genbei arranged for him to attend the academic and martial training of the Jishūkan (時習館), the local academy, and apparently the boy did not demonstrate any particular skill with the sword; in this regard he apparently commented "Kenjutsu (Japanese fencing) with bamboo shinai is nothing but a game."
He was called to serve in the Jishūkan. At the age of 16 he was called to serve in the castle of Kumamoto as a cleaner (お掃除坊主 osōji-bōzu); despite the low level of the task, the boy devoted himself to it with passion, and in his spare time he learned sado and ikebana.
In this period he also met two characters who would have great relevance in the activities of the ishin shishi: Todoroki Buhei and Miyabe Teizō. In discussions with them he became interested in the concept of kinnō (勤王), or loyalty to the emperor.
Having come of age, he chose the name Gensai.
In 1851 he entered the service of Hosokawa Narimori, daimyō of Kumamoto, and followed him to Edo for his sankin kōtai. During this period occurred the episode of the black ships, which marked him deeply.
In the shogunate had long been in force a policy (sakoku) that isolated the country from the rest of the world, but in 1853 the U.S. Navy, anchoring four warships off the coast of Edo, forced the shogunate to abolish that law and accept a process of westernization and openness to foreigners;
This forced change of course weakened the authority of the shōgun, and led many to call for the return of power to the Emperor, who for several centuries had lost all political authority and had only the role of religious leader.
To this group belonged Gensai, who left Edo enraged and returned to Kumamoto, where he entered the Gendōkan academy of the philosopher kinnō Hayashi Ōen before returning to Edo.
Gensai was in Edo when the assassination of Ii Naosuke took place, and when some of the assassins entered the Kumamoto mansion he called a doctor for them, invited them to a tea ceremony, and confessed his admiration for their action.
In 1861, Gensai married Misawa Teiko, daughter of another Kumamoto vassal and a skilled fighter, particularly gifted in the use of the naginata; their son, Gentarō, would survive Gensai's execution thanks to Teiko's intervention.
In 1862, he joined the Kyōto Guard Corps sent by the Kumamoto clan; however, after a short time he abandoned his position as bōzu, and shortly retired from the service of the Kumamoto, to join the ishin shishi.
His extremely fast sword technique belonged to the Furanui kenjutsu style, also known as Shiranui-ryu; thanks to his skill he soon became part of the Four Hitokiri of the Bakumatsu, an elite group of assassins dedicated to the political assassination of the Emperor's enemies;
the group also included Nakamura Hanjiro (also known as Kirino Toshiaki), Tanaka Shimbe, and Okada Izō, but Kawakami soon became known as the most ruthless of the group.
In 1864, his mentor Miyabe Teizō died in a Shinsengumi raid on Ikedaya; not long after, Gensai carried out the murder that made him famous, and the only one that can be attributed to him with certainty;
that of Sakuma Shōzan, a prominent Japanese politician and scholar in favor of the foreign presence in Japan; the murder caused a particular stir because it occurred in a single slash and in broad daylight. Although other killings have been attributed to him, that of Shōzan is the only one proved by the evidence against him.
When his fame became an obstacle to his actions, he retired to the Chōshū and joined the military actions of Takasugi Shinsaku's Kiheitai against the shogunate's military expeditions in the region.
However, during an action in Kokura, he was captured by Kumamoto forces, and imprisoned until the beginning of the Meiji Restoration.
After the Meiji Restoration and the end of the samurai, Gensai changed his name to Takada Genbei, and devoted himself to teaching samurai philosophy, but his isolationist ideas did not find a place in the new imperial government, which contrary to his hopes looked favourably on the opening to foreigners and even saw in him a threat to the future of the nation:
accused of having offered refuge to former members of the Kiheitai, he was arrested and sentenced to public execution in the fourth year of the Meiji era (1871).
The figure of Kawakami Gensai inspired several later Japanese works; in particular, the character of Kenshin Himura, the protagonist of the series Kenshin Samurai vagabond by Nobuhiro Watsuki, is based on him.