Nemuri Kyoshirō (眠 狂四郎?) is a series of jidaigeki novels written by Renzaburo Shibata. The stories were originally serialized beginning in May 1956 in the Shūkan Shinchō.
The stories take place during Edo period under the Tokugawa shogunate and the rules of Tokugawa Ienari and his successor Tokugawa Ieyoshi and center on the title character, a sleepy-eyed rōnin or outlaw swordsman who is the son of a Japanese mother (the daughter of a daimyo, who commits jigaki [see "Female Ritual Suicide" in Seppuku] some time after Kyoshiro's birth) and a foreign father, and who was conceived during a Black Mass (and as a result has a fierce hatred for what he considers the hypocrisy of Christianity).
Seven full-length novels and eight short stories in the Nemuri Kyoshirō series were published in Japan.
"Nemuri Kyoshiro" was first played by Tsuruta Koji in three films released by Toho Studios:
From 1963 to 1969, Ichikawa Raizo played "Nemuri Kyoshiro" in the Daiei Studios series. Animeigo released the first six films of the Daiei series on VHS and the first five on laserdisc under the title of Sleepy Eyes of Death. Animeigo later announced that it had renewed their licensing rights to the series and released a boxed set of the first four films on DVD in 2009. A second boxed set containing the next four films was released in Summer 2010 (which marked the first official release on DVD in the United States of The Mask of the Princess and Sword of Villainy ). The third box-set came out in 2013.