A1
の — joining two nouns
How の links nouns in Japanese, why the modifier comes first, and the range of relationships one particle covers.
の joins two nouns, and the first one describes the second.
私の本。
Watashi no hon.
My book.
日本の車。
Nihon no kuruma.
A Japanese car.
The order is backwards from English. Book of mine is the literal shape: owner first, thing second. Whenever a Japanese phrase feels inside out, this is usually why.
It covers more than possession
One particle does the work of English of, ’s, from, in, for and a bare noun-noun compound.
大学の学生。
Daigaku no gakusei.
A university student.
木の机。
Ki no tsukue.
A wooden desk.
東京の友達。
Tōkyō no tomodachi.
A friend in Tokyo.
Nothing marks which relationship is meant. Context does it, and in practice it is almost never ambiguous.
Chains
の can repeat, and the chain reads right to left into English.
友達の車の鍵。
Tomodachi no kuruma no kagi.
My friend’s car key.
Not with adjectives
の joins nouns. An adjective attaches on its own — that is what makes it an adjective.
高いの山。
高い山。
高い is an い-adjective and needs no particle. の would only appear if the first word were a noun. See adjectives.
な-adjectives look like an exception but are not: 静かな部屋 uses な, not の, and that な is the marker of its class.