“I write fiction, but I experience the fiction I write,” the Japanese writer Yuko Tsushima wrote, in 1989. “In that sense, they are not fiction anymore, but reality.” Tsushima, who died in 2016, was the daughter of the novelist Osamu Dazai, who committed suicide when Tsushima was barely a year old. In her novels, the protagonist is often shadowed by a death in the family—an event that, because of its suddenness, can never be mentioned. The narrator of “Territory of Light,” which has just been published in the U.S., in an English translation by Geraldine Harcourt, describes growing up in a house where her father’s room had been kept intact despite his untimely death.