I. THE HEART OF THE PROBLEM THE Japanese population will not reach the higher of the figures expected both by many Japanese themselves and by many foreign observers. Factors are already at work, and in the future they will be at work more and more powerfully to exert a drag on its rate of increase. The marriage rate is shrinking, and it is likely that the 1930 census results will show (what is usually the same thing) a not insignificant retardation in the average age of marriage. Moreover, the fecundity of Japanese families, which has been declining throughout the last two decades, has now begun a fairly sharp fall. And the spread of contraception, perhaps encouraged and organized by the authorities, will guarantee the continuance of the fall. But the full effects of these skidding factors will be delayed for a generation or more by reason of the peculiar age-composition of the Japanese population. The death rate (the crude death rate) is about to decline, while the birth rate (the crude birth rate) will remain high, though not necessarily and not probably as high as hitherto. The death rate is about to decline because there will be born a lesser proportion of children to the total population, and because the old-age group will be unusually small; that is to say, the two groups where the death rate is highest will be unusually small in proportion to the total population, so that death will remove a smaller proportion each year than normally. And the birth rate will remain high because of the abnormally large proportion of the population in the childbearing group. In consequence we are to expect that it will be twenty or thirty or more years hence before a pronounced turn towards a stationary level is made, and that at least 15 to 20 million persons will be added to the present numbers before then.