Broad coverage?

The Japanese health insurance system is designed to cover you anywhere in Japan, though prices vary from region to region.

If you are on a business trip, your health insurance will also cover you overseas. If you are on holiday, it is advisable to take out travel insurance before you go. Some local authorities have been known to reimburse policyholders for medical expenses incurred overseas while traveling, though this is an entirely case-by-case system and should not be counted on.

If you leave and then attempt to rejoin the the Japanese insurance system, you are obliged to pay up to two years worth of back premiums.