Tokyo vs capital of Japan

Tokyo and capital of Japan both are nouns.

Word	Noun	Adjective	Verb	Adverb
Tokyo	Yes	No	No	No
capital of Japan	Yes	No	No	No

As nouns, Tokyo and capital of Japan are synonyms defined as:

Tokyo and capital of Japan: the capital and largest city of Japan; the economic and cultural center of Japan

Other synonyms of Tokyo include Edo, Japanese capital, Tokio, Yeddo, Yedo.

Tokyo (noun)	capital of Japan (noun)
the capital and largest city of Japan; the economic and cultural center of Japan	the capital and largest city of Japan; the economic and cultural center of Japan