This study investigates the effect of a wife’s employment on the risk of divorce and its change over time. The analysis uses data from the Japanese Panel Surveys of Consumers (1993–2020) and provides the following findings. First, a wife’s employment increases the risk of divorce, and its total effect is generally stable across marriage cohorts. Second, net of her employment status, the effects of the wife’s absolute earnings on the risk of divorce have changed across marriage cohorts and are negative for the post-2000 cohort. Third, because of the above changes, an “inverse U-shaped” relationship—in which divorce is most likely to occur when the wife is a non-regular employee with low earnings and least likely to occur when she is unemployed with no earnings or a regular employee with high earnings—emerged among the couples married after 2000. These results imply that persistence and change coexist in the gendered nature of marriage in contemporary Japan.

Kiyomi Morioka, the first president of our Japan Society of Family Sociology and a great leader of family sociology in postwar Japan, passed away in January 2022 at the age of 98. This special issue aims to commemorate Morioka by summarizing his family sociology and examining its implications for contemporary family research. This special issue is based on the theme sessions of the academic conference held in September 2022 and focuses on modern family research and traditional family “Ie” research, with the addition of the theme of theory systemization and family change theory. All of the authors are from the generation that was educated under the so-called “Group Theory Paradigm” of postwar Japan established by Morioka. For this reason, this special issue has the character of being a summary from a standpoint whose research style is similar to that of Morioka. Compared to Morioka’s time, the family itself and the theories and methods of family research have become more diverse. Morioka’s research may be viewed differently by today’s younger generation and those with different research perspectives. We hope that this special issue will be the starting point for a wide range of examinations from various standpoints.

The purpose of this paper is to evaluate the trajectory of Kiyomi Morioka’s research from a contemporary perspective in relation to postwar Japanese family sociology and family change. Dividing his research trajectory into four stages, he determined the research topics to pursue in each stage by examining and reflecting on his achievements in the previous stage. After the preparatory first stage, he established the nuclear family theory and summarized the family cycle theory in the second stage. However, at this time, Morioka recognized the limitations of the family cycle theory and expected to overcome these limitations in the third stage by means of the life course theory. At the same time, he showed a strong desire to develop his own theory of family change, but he was unable to achieve satisfying results. In the midst of the increasing dissolution of families, such as “individualization,” and the trend toward diversification in family research, he entrusted the challenge of a paradigm shift to subsequent generations.

Among the great achievements of Kiyomi Morioka, who passed away last year, I will focus on the construction of a theoretical system of family sociology and reexamine the structure of his family theory, which is known as the “group theory paradigm.” While highly appreciating the results of his efforts in system building, I have pointed out certain inadequacies in the theorization of family dynamics and presented several issues that should be passed on to future research on family sociology.

Kiyomi Morioka has undoubtedly played a significant role in Japanese family studies. The classification and typology of family are the foundation of Morioka’s research on family. This paper focuses on Morioka’s ideas regarding the stem- and conjugal- family systems and examines their problems. Morioka’s notions of the stem- and conjugal- family systems, to which he devoted much of his research life, are based on combinations of the existence or non-existence of two elements: the principle of co-residence with the children’s family and the lineal reproduction of the family. The reason for this can be identified by tracing his process of concept formation. The origin of Morioka’s concept of family typology lies in Eitaro Suzuki’s theory that conceptualized the direct lineal reproduction typical in traditional Japanese families. Morioka’s typology reconstructed this concept using George P. Murdock’s nuclear family theory; however, Morioka’s typology could not eliminate the typicality of Japanese families.

This article focuses on Kiyomi Morioka’s research on “Ie,” mainly on the Shinshu organizaitons and Japanese modern aristocracy, in order to investigate the implications of his research for today. First, relationships among Morioka’s various concepts of “Ie” will be reviewed, and then, using Teizo Toda as a guide, Morioka’s concern with institutional theory will be reviewed. Furthermore, an overview of how these perspectives are used in social analysis in the study of the Shinshu organizaitons and the modern aristocracy will be given. Through these considerations, this article will reconsider Morioka’s perspective on long-term family changes in Japanese society and confirm that his interest in institutions is derived not from a static or non-historical perspective, but rather from a dynamic life-course perspective on how people lived their lives in the midst of historical, social, and political changes.