forthcoming post on maternity leave (see next week).
It seems that the Japanese process typically involves a 6+ day stay in hospital for mother and baby, during which time you learn about aftercare for your newborn etc. Understandably, this isn't a cheap period of your life. Luckily, provided you're paying the shakai hoken (social health insurance) you can expect to get the vast majority of that money back, if not more.
In fact, even if you don't stay the full time, or even don't go to hospital at all and find your own midwife, you'll still get that money (approx. 420,000yen depending on your area).
For more, here's an extract from a recent article in the Japan Times: