A colleague there, a urologist, had been collecting haiku from patients who had written them during their lengthy treatments for sexually transmitted infections, intending to publish them in a mimeographed edition.

Saitō was initially uninterested, thinking haiku "old-fashioned stuff", but he gave way to the repeated entireties and began to compose his own poems.

[1] Despite starting at an uncharacteristically late age and eschewing any kind of mentorship or apprenticeship to a more experienced writer, Saitō quickly became a leading haiku poet.

[1][2][3] A bout of tuberculosis prompted Saitō to reassess his priorities, and he abandoned dentistry to devote his life to haiku, paying the bills with a desk job at a company owned by mountaineer Mita Yukio (1900-1989), a friend from Singapore.

[1][2][3] Unfortunately, with an ultranationalist wartime government bent on repressing any hint of dissent, Saitō and other Kyōdai Haiku were arrested by the secret police in 1940.

At first he lived in an old hotel filled with foreigners and bargirls, but as World War II dragged on, fear of air raids prompted him to rent a large, crumbling rural house that was later dubbed the "Sanki Mansion."

His interactions with colorful characters, sailors and soldiers on all sides of the conflict, and the black market for everyday necessities were chronicled in a series of stories that he published in the magazines Haiku and Tenrō in the 1950s.