After having maintained about replacement level for some 15 years, Japanese fertility has been declining since 1973. The application of decomposition technique to the decline in the crude birth rate between 1973 and 1980 clarified that 40% of the total change in CBR is explained by changes in age composition, 50% by the decline in proportions of couples married, and 10% by a short-term decline in marital fertility. The change in age composition in this period refers to the abrupt shrinkage of the younger cohort, which is most exposed to the prospect of marriage: those aged in then 20's. This is, in turn, an echo of the precipitous decline in birth just after the short-term "baby boom" in postwar years. If we take into account the historical steadiness of marriage throughout Japan, the decline in the proportions of those married would seem to be the postponement of marriage without any rise in the celibacy rate. Several factors are presumably conducive to the recent marriage squeeze, but the recent rise in high school and college enrollment rates for both men and women appears to be most responsible for it. It remains to be studied whether the disequilibration of the sex ratio among marriageable cohorts due to the abrupt change of the cohort size, the decline in substantive wage rates since the oil crisis of 1973, or changes in the social mechanism for selecting spouses (i. e., the decrease in arranged marriages), is causally relevent to the marriage squeeze. The cause for the short-term decline in marital fertility is difficult to discern. According to several recent fertility surveys of married women, there has been little change in completed fertility, fertility goals (measured by the total intended number of children), and fertility control behavior (which is measured by the proportion of contraceptive usage or induced abortion, the timing in the initiation of contraceptive usage, and the contraceptive methods used). Thus, the short-term decline in marital fertility, if any, is inferred to be temporary.
