Japanese Islands vs Japanese Archipelago

Japanese Islands and Japanese Archipelago both are nouns.

Word	Noun	Adjective	Verb	Adverb
Japanese Islands	Yes	No	No	No
Japanese Archipelago	Yes	No	No	No

As nouns, Japanese Islands and Japanese Archipelago are synonyms defined as:

Japanese Islands and Japanese Archipelago: a string of more than 3,000 islands to the east of Asia extending 1,300 miles between the Sea of Japan and the western Pacific Ocean

Other synonyms of Japanese Islands include Japan.

Japanese Islands (noun)	Japanese Archipelago (noun)
a string of more than 3,000 islands to the east of Asia extending 1,300 miles between the Sea of Japan and the western Pacific Ocean	a string of more than 3,000 islands to the east of Asia extending 1,300 miles between the Sea of Japan and the western Pacific Ocean