We say that we cannot use definite articles such as "the" with country whose names start from great, upper, lower, western, eastern, southern, northern, south etc. So we use "the" with country name such as "the united states of america" and "the united kingdoms". Then why we not use it with the countries names such as INDIA, GERMANY, CHINA, JAPAN as it does not contain any of the word such as great, north etc. Please answer me fast.
Usually, an article is not used before the names of countries. However, when the name of a country includes nouns like state(s), kingdom, republic or union, adding an article is necessary. Therefore, we write 'the United States of America' or the U.S.A., the United Kingdom or the U.K.