Shikoku vs Japan

Shikoku and Japan both are nouns.

Word	Noun	Adjective	Verb	Adverb
Shikoku	Yes	No	No	No
Japan	Yes	No	No	No

Shikoku (noun)	Japan (noun)
the smallest of the four main islands of Japan; to the south of Honshu and to the east of Kyushu; separated from Honshu by the Inland Sea; forested and mountainous	a constitutional monarchy occupying the Japanese Archipelago; a world leader in electronics and automobile manufacture and ship building
	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