mily due to mortality reduction, general rise in level of living, urbanization, industrialization, etc., would have also been fairly important for contributing to determine the average household size. This is again not a very recent one, but according to a decomposition study for Japan attributing to various factors the difference between average household sizes in different years, the effect of fertility decline explains 70 percent of the contraction in the average household size from 1955 to 1965; 20 percent were attributed to internal migration and the remaining 10 percent attributed to the nuclear fission, which in turn presumably originated from economic and social factors, notably from the rise in per capita income, urbanization,enhancement in education, and the emergence of individualism, etc. (Kono,1969).
C. Change in the Family Structure
When the size of household diminishes, so does the structure of the family change. For example, a recent article by Weinstein and others,(Weinstein et al, 1990) also signifies some trend of family nucleation and decline in the stem or joint type pf families in Taiwan.
The overall picture is, however, not simple. As shown in Table 10,according to the census statistics on households by type, the proportion of nuclear family households has been relatively stable since 1975 without a sigh of significant increase, though the type of "other related households"which practically means that of three-generation families shows a very clear trend in decline. It can be argued that this trend of non-increase in proportion of nuclear families is partly due to the rapid fertility decline which in turn causes the decreased supply of married sons eligible for nuclear families, that is non-eldest sons, if the propensity for living with the married eldest son does not substantially decrease (Yi,1986; Hiroshima, 1988).
But anyway, it can imply the tenacity of the stem-family orientation in Japan like any country in East Asian Region. Even though there are strong currents flowing towards modernization and concomitantly industrialization and urbanization, the traditional cultural influences imbued with Confucianism and kin-orientation are so strong a force as to foster the way of life supporting an perpetuating the three-generation family mode. In the case of Japan, however, in reference to Table 10, substantial increase is noted for one-person households. If these one-person households are added to the nuclear-families, then what may be called "nuclear-family like"households demonstrate a clear trend of increase.
