The sociologist and feminist Ueno Chizuko has released a collection of past essays that examine Japanese literature as primary source material reflecting the society and era in which it was written.
"Ueno Chizuko ga Bungaku o Shakaigaku Suru (Ueno Chizuko Does Sociology on Literature)" (Asahi Shimbunsha) touches on several topics. Among them are gender differences in the language of male and female writers of the 20th century, feminist issues raised by writings on the Red Army, and the relationship between the traditional concept of the mother in Japan and the patriarchal family system. I found particularly interesting her essay on the way in which the issue of kaigo (caring for the elderly) has been treated in literature.
She very effectively compares two autobiographical novels, Ariyoshi Sawako's "Kokotsu no Hito (The Twilight Years)," published in 1972, and Sae Shuichi's "Koraku (Falling Leaves)," written over 20 years later in 1995. The former was a pioneering work in taking up the emerging issue of an aging society and sold over 2 million copies. "Koraku" followed up on the same topic, and perhaps partially due to the novelty of it being written from a male perspective, sold some 200,000 copies.