TOKYO — Ayaka Okumura was barely pregnant when she began fretting over how she would hold on to the management job that would have been out of reach just a generation ago, when Japanese women were often relegated to dead-end “office lady” jobs pouring tea and greeting guests.

From the start, Ms. Okumura had a crucial advantage over the many American women who despair of “having it all.” The Japanese government subsidizes thousands of day care centers nationwide for families of all income levels, and it demands that caregivers pass rigorous exams in child care that usually require two years of special schooling.

But the quality of the public day care network — and a growing shortage of slots as more women entered the work force — has created its own set of seemingly intractable problems. Increasingly desperate women are forced into an annual competition for day care slots that is grueling enough to merit its own name, “hokatsu,” and is said by some to surpass the notorious, stress-filled job hunt endured by Japanese college students.

Ms. Okumura is now a weary veteran of that day care campaign.

For months, as her stomach grew larger, the mother-to-be, then 30, trudged from day care center to day care center, some public and some private, in what little time she could manage away from her job, putting her name on waiting lists that were sometimes more than 200 names long.