Japan National Tourism Organization has launched a website with which you can search medical agencies that are able to assist international tourists.

Hundreds of medical institutions are listed with an easy searching system. You can find the best one depending on your location, symptom, language, etc.

The website also tells you how to use medical institutions in Japan.

It is worthwhile taking a look and be prepared just in case of an emergency.

http://www.jnto.go.jp/eng/arrange/essential/emergency/mi_guide.html