I'm in Japan right now. I don't have any insight into government response, but there could be cultural factors that could have reduced the spread of the virus. In general, the Japanese avoid physical contact. They bow when they greet each other, money is exchanged on a tray rather than by hand, they typically don't hug, etc. Plus many people wear face masks. Occasionally when I bought something from a store, they would throw in a free face mask for me as well. And many businesses and restaurants put hand sanitizer at their enterance.