Is it possible to cover the entire area of Japan with a single satellite image?

Although it depends on the satellite, there are many satellites with an observation range of several tens to several hundreds of kilometers. The widest observation range is that of the U.S. satellite Suomi. It has a range of 3,000 kilometers, so almost the entire Japanese archipelago is covered. Also, the weather satellite Himawari covers a wide range of Asia including Japan.
For your reference, we have published an article in Tellus owned-media which summarizes the different views available from satellites.

▼Can people be seen from artificial satellites?-- Summary by satellite, ground resolution and local time