Japan had a lot going against it:
An elderly population
Lots of smokers
High population density
Heavy use of public transportation where they pack in like sardines every morning
A ship packed with COVID docked in Tokyo that was visited regularly by Japanese doctors who were not themselves tested
Poor nationwide testing
Minimal effort to lock down - only a few major tourist attractions were closed, restaurants and bars are still open
Limited travel restrictions - they limited people coming fromWuhan, but allowed travelers from other parts of China
One of the earliest countries to see community spread
And they have one thing going for them: everyone wears masks. Especially now, but even in an ordinary spring, 1/3 of Japanese will be wearing masks either to guard against seasonal allergies or prevent the spread of colds and flu. Now, you’d be hard pressed to find anyone in Tokyo not wearing a mask, and the English language papers remind westerners in Japan to mask up.
Here in the US we had a lot going for us, but the government told us not to wear masks because they said masks don’t work (oh, and save them for medical personnel because somehow masks do work for them).
And here we are.