allows businesses to export wealthy retired persons to various resort areas in several countries such as Australia and Canada (Martin, 1989), it prohibits business firms from importing labor except for those with highlyspecialized skills such as foreign language teachers and professional athletes (Ogawa, Jones, and Williamson, 1993). The proportion of foreign nationals in the Japanese labor force is the lowest percentage among the industrialized nations (Abella, 1989).
In June 1990, the Immigration Law was amended to tighten a further inflow of illegal foreign workers. Unlike the case of Singapore, it is not foreign employees but employers that are penalized; as for the maximum penalty faced by the employers, the revised provision includes imprisonment up to three years or a fine up to 2 million yen. One additional important feature of the 1990 amendments is that a training program with the quota imposed was instituted. The total number of foreign trainees (who are actually unskilled workers) should not be more than 5 percent of the employees working for each firm; this implied that firms with less than 20 workers were not allowed to have any foreign trainees.
Another labor-related policy option is to raise female participation in the labor force. The age-specific labor force participation rates of Japanese women still show a M-shaped pattern, although participation among middle-aged women has been rising in recent years primarily due to their higher education, shortening of the reproductive span, and a more modern life-style (Shimada and Higuchi, 1985; Ogawa and Clark, 1995; Ogawa and Ermisch, 1994). It should be stressed that slightly more than half of married women working as paid employees are part-time workers, and that this proportion has been growing at a rate faster than that of fulltime workers since the late 1970s (Ogawa and Retherford, 1993a). This increased importance of part-time employment is related to the income tax rules; those who earn more than one million yen a year must not only pay income tax but also lose their dependent status in their husbands' payroll and social security plans. The removal of these tax rules is expected to lead to a further rise in the participation of middle-aged women in full-time paid employment.
To raise married women's participation in the work force, the government has also been attempting to improve the availability of day-care centers by extending their service hours rather than by increasing the number of day-care facilities. At present, although the supply of day-care facilities for preschoolers is reasonably sufficient, only 28 percent of married women with children aged 0-5 are using day-care services (Population Problems
