Japan originally had many countries, each called by various names. These small countries existed more than 1,900 years ago. At that time, they were not yet united into a single country called Japan.
Later, these countries gradually came together. They did not come together all at once, but gradually became one country. The country thus created was named Yamato at first.
At that time, however, the Chinese called Japan "Yamato. The word "wa" is a Chinese word meaning "very small" or "tiny. From the perspective of China, which had a much longer history than Japan, Japan at that time was still a small country with little presence.
Gradually, however, the Yamato nation grew larger and more powerful. It became increasingly difficult for Yamato to be referred to as a "small country" by the neighboring Chinese people, a term that meant "tiny. So, about 1,400 years ago, a man named Prince Shotoku of the Yamato Kingdom wrote a letter to China.
In this letter, the word "Japan" was not used yet. But he used the word "Hiizuru Tokoro" instead of Yamato no Kuni.
Hi-izuru-okoro" means the place where the sun rises. Japan, which is located in the east from China, is the country where the sun rises.
It is thought that "hi-izuru tokoro" was changed to "hinomoto" and then to "Nihon" (Japan).