Getting detailed with relative clauses

Relative clauses are statements that are embedded inside other statements. If we take a structure like “A is B”, a relative clause allows us to expand it as much as we want with something like “A is (B that is C)” and then “A is (B that is (C that does D))”. In English, this may look unwieldy, but in Japanese it is very common.

In this lesson we're going to cover relative clauses that modify nouns. Relative clauses that modify nouns are things like “I used to live in” in the sentence "That is the house I used to live in".

To make a verb modify a noun directly, you just attach the verb right before the noun. This means that Japanese verbs can basically act like adjectives.

食べる人
Person that eats

私にくれる人
People that give to me

The simple tense of だ cannot make a relative clause because it cannot be connected directly to the left of a noun, but its past tense can.

*必要だ食べ物です
(ungrammatical)

好きだった食べ物
Food that I liked

In rare circumstances, that rule can be broken, but it's a real rule, not a fake one. Don't make relative clauses that end with だ.

In short relative clauses, の can be used to replace the が particle used to mark the subject. This の as a replacement of が can only happen in relative clauses, as long as the を particle is not being used in that very same clause.

君の来た場所
The place where you came (from)

私の食べたラーメン
The ramen I ate

私がラーメンを食べたレストラン
The restaurant I ate ramen at

In the last example, の cannot replace が as 私のラーメンを食べたレストラン would assume a very different, borderline nonsensical, meaning (“The restaurant that ate my ramen”).