Flower and Snake (novel) 花と蛇
Dan Oniroku's long SM serial, begun in Kitan Club in 1962 and finished in 1975, the source of the Nikkatsu and Toei film series and a classic of Japanese SM fiction.
Flower and Snake (Hana to Hebi) is the SM novel that made Dan Oniroku’s name. According to his official chronology, he sent the first part to Kitan Club in 1961 under the pen name Hanamaki Kyōtarō, at a low point in his life, and the magazine printed it over three issues in 1962 to a strong reader response. Japanese Wikipedia dates the start of the serial to the August 1962 issue.
Dan initially declined to continue. The chronology says that Kitan Club’s editor Yoshida Minoru kept asking, and that in 1963 Dan resumed the story under the new name Dan Oniroku while working as a schoolteacher. The first run ended after fifteen installments in 1964 and was immediately followed by a sequel. Japanese Wikipedia reports that the serial later moved to the magazine Ab Hunter and ended in September 1975, roughly thirteen years of intermittent writing.
The novel has been reissued many times. Japanese Wikipedia lists editions from Tanbikan (1969–1970), Kadokawa Bunko (1984–1985), Fujimi Shobō (1985–1986, described as the first complete edition) and a ten-volume Gentōsha Outlaw Bunko set (1999), among others. It is best known through its adaptations: the Nikkatsu film of 1974 and its sequels, four Toei films between 2004 and 2014, an animated video, a game and a 2007 stage production.