It was considered a landmark in Japanese realism and is thus regarded as the first Japanese naturalist novel. It is a story of a "burakumin" schoolteacher who keeps his outcaste status secret until near the end of the novel. While Tōson was writing it each of his three children died of illness. His second novel, "Haru" (春 "Spring", 1908), is a lyrical and sentimental autobiographical account of his youthful days with the "Bungakukai" group of writers. His third novel, "Ie" (家 "The Family", 1910–1911), is considered by many to be his masterpiece. It depicts the slow decline of two provincial families to whom the protagonist is related. Tōson created a major scandal with his next novel, "Shinsei" (新生 "New Life", 1918–1919). A more emotional work than "Ie", it is an autobiographical account of his own extramarital relations with his niece, Komako, and the knowledge that her father (his elder brother) knew of the incestuous affair, but concealed it. When Komako became pregnant, Tōson fled to France to avoid the confrontation with his relatives, abandoning the girl. Tōson attempts to justify his behavior by revealing that his father had committed a similar sin and that he could not avoid the curse of his lineage. The general public did not see it that way and Tōson was censured on many fronts for his behavior and for what was perceived as a gross vulgarity by attempting to capitalize on the disgraceful incident by turning it into a novel. On his return to Japan, Tōson accepted a teaching post at Waseda University. He then wrote "Yoakemae" (夜明け前 "Before the Dawn", 1929–1935), a historical novel about the Meiji Restoration from the point of view of a provincial activist in the Kokugaku (Nativism or National Learning) school of Hirata Atsutane. The hero, Aoyama Hanzō, is a thinly veiled representation of Tōson's father, Shimazaki Masaki. After greeting the restoration of direct rule by the Emperor as a restoration of Japanese national tradition, the protagonist ends up dying in bitterness and disappointment. "Yoake mae" was serialized in the literary magazine "Chūō kōron" and was later published as a novel in two volumes. In 1935, Tōson became the founding chairman of the Japanese chapter of International PEN.