If you know how to look at this map, you can deduce a lot of Japan’s history, why it has the borders it has today, where they are contested, and why it went through the wars it did.

What can you see?

The Four Main Islands

The three big islands of Honshu, Kyushu, and Shikoku were destined to be a political unit:

• They are very close to each other

• They’re also oriented mostly east–west. That means they share the same climate, which facilitates movement, because people’s lifestyle and crops don’t change.

Hokkaido is much farther north, which means different climate and ways of life, so unifying with the other islands would be harder. But the island is so close (~19 km, 12 mi) to Honshu that it was very likely to ultimately unify with Japan. All this explains a lot of Japanese history, like for example, why the three southern islands of Japan united partially for the first time over a thousand years ago, and why Hokkaido was only fully conquered and colonized at the end of the 1800s.

These four islands are not isolated in the middle of an ocean. There are five paths to reach them.

The Five Gates to Japan