Japanese capital vs Tokyo

Japanese capital and Tokyo both are nouns.

Word	Noun	Adjective	Verb	Adverb
Japanese capital	Yes	No	No	No
Tokyo	Yes	No	No	No

As nouns, Japanese capital and Tokyo are synonyms defined as:

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

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

Japanese capital (noun)	Tokyo (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