capital of Japan vs Tokio

capital of Japan and Tokio both are nouns.

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

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

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

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

capital of Japan (noun)	Tokio (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