was a Japanese author, known as the creator of the Kogarashi Monjirà  novels, which became a hit televised drama series.
He was a self-declared member of the or "new orthodox" school of detective fiction writing. Aside from mysteries, he also wrote thrillers, essays and history books, with some 380 books to his credit.
Saho Sasazwa was born , the third son of poet . Born in Yokohama according to many sources, but it has also been said he was actually born in Yodobashi, Tokyo and later moved to Yokohama. There he attended what is now Kanto Gakuin University's high school division, but failed to graduate, frequently running away from home during this period.
By 1952 he was in Tokyo, working at the Bureau run by the Postal Ministry. Around this time he dabbled in writing plays.
In 1958, he was struck by a DUI car, suffering injuries expecting to take 8 months to fully heal. But his short stories and , which he had submitted to prize contest before the accident both qualified and were printed in the December 1958 special issue of the Hoseki magazine.
In 1960, his became a runner-up for the 5th Edogawa Rampo Prize, and the release of this in book format marked his debut as novelist.
He adopted the pen name Saho, which was taken from his wife's name .
His was awarded the 14th Mystery Writers of Japan Award, after which he resigned from the Postal Ministry and became a full-time professional writer.
With his (1962) he received his third nomination for the prestigious semi-annual Naoki Prize for popular fiction. He had been twice nominated for the prize before, for Hitokui and , and although he was short-listed to win this time, he was disappointed once again. Around this time, while declaring himself to be one of the practitioners of honkaku-ha () or "orthodox school" of mystery fiction-writing, he wrote a trilogy on double-suicide without homicide; of these, the Naoki Prize-nominated Roppongi Double-Suicide was appraised as a piece "depicting empty love between a young man and a girl", which entwined "the drama of loss of faith in humanity" into the mystery novel.
In 1970, he ventured into writing period novels (in particular matatabi fiction about traveling gamblers) with . Sasazawa's style of this gambler fiction has been characterized as "casting a nihilistic shadow, an added an aura of Cowboy Westerns". The samurai period gambler piece that brought Sasazawa lasting fame was his Kogarashi Monjirà  series, begun with the episode entitled . The book was TV-dramatized with Atsuo Nakamura playing the leading role of the gambler Monjirà Â, and the program achieved immense popularity.
He continued to write fiction in both contemporary and period settings.
Some of his outputs in modern settings from the subsequent period include the child-kidnapping novel , called a masterpiece on par with his earlier great works; which launched the Detective Isenami series; was a time-limit kidnapping story with a twist, the scandal-monger must devise a ransom for the perpetrator who only wants vengeance; features a well-crafted locked room gimmickry.
He also became well known at one time for Akuma no heya ("Devil's room", 1981) and its sequels in his Akuma ("Devil") series of erotic suspense-thriller novels (), this being a hybrid genre between the erotic novel and suspense-thriller.
His started the Hideo Yoake casefile series of novels, dramatized on TV as the starring Tsunehiko Watase; The TV series "Interrogation room" ran its first episode in 1994 based on the novel of the same title published 1993.
Period pieces in other than his Monjirà  include which employs mystery novel techniques in historical settings, the Jigoku no Tatsu crime-solving novels (1972âÂÂ), televised as ; another TV-dramtized series on (1974âÂÂ), whose title character Okon bears a tattoo which forms a complete dragon when combined with her lover's.
During his lifetime he published some 377 books.
With declining health in 1987, he recuperated at a hospital in the town of Mikatsuki, Saga which bore a name similar to (Mikazuki Village), the fictitious birthplace of Monjirà Â. After being discharged, he made the adjacent town of Fujichà  his home, and although he had to relocate in 1995 to in Saga city for hospital access, the Fujichà  residence later became the Sasazawa Saho Memorial Museum.
He established the for literature by new authors in 1993, with the final 24th prize awarded in 2017.
In 2001 he returned to Kodaira, Tokyo, and succumbed to liver cancer (HCC) on 21 October 2002 at a hospital in Komae, Tokyo.
He was a prolific writer, who at his height wrote 1,000 or even 1,500 pages of manuscript per month,ãÂÂhe has been called a "constant innovator" or experimenter. In particular, Sasazawa is known for applying the mystery novel techniques of "surprise-twist endings (donden-gaeshi)" and climatic endings in writing matatabi fiction, thus introducing a fresh angle in the fiction about these wandering rogue swordsman-gamblers.
He wrote a study in sensual-erotic suspense with the novel which was adapted into film, and crime novels consisting entirely of conversation, such as , and , and where the alibi trick undergoes a complete 180-degrees plot-twist.
He held a staunch purist stance about detective fiction writing. Sasazawa identified himself as a proponent of the . Such a writer, he explained, was not only required to be "orthodox" (or "authentic") and devise a clever trick used in the crime, but in addition, needed to maintain realisticness in the human characters employed. When he sat on the selection panel for the Edogawa Rampo Prize, he repeatedly bewailed the laxening of the definition of what could be considered "detective fiction". In 1977, he wrote an essay that polemicized against the novel of manners contaminating the mystery fiction genre.
Donta's caebook.
Or, "Full knowing it's a Dream" series
, Kobunsha
Otasuke Doshin or the "Helpful Doshin-Detective"