Why does Japan call the United States the United States and Germany the independent country?

The United States of America, [1] referred to as the United States (U.S.A), the country of wheat, the country of the United States, is also often called the United States, U.S, The U.S, USA, The States or America in English. . America is named after the Italian navigator Amerigo. Nicknamed "Uncle Sam". It was formerly known as "Citi Country" in Chinese. In the cultural circle of Chinese characters, China calls it Germany. In Japan, it is called "Duyi" or "Duyi", or "Duyi" for short. North Korea established diplomatic relations with Germany in 1883. It was originally called Germany (?) along with China. As North Korea became independent from China and was colonized by Japan. After the 20th century, it was renamed Duyi (?).