Page 226 - Basic Japanese

Something special happens when a copula clause, like sakka
desu ‘he is a writer,’ is used as a modifier clause. To mean

‘my friend, who is a writer,’ they do not say sakka da
tomodachi but sakka no tomodachi. Now, this no is not the

particle that shows that one noun modifies another—it isn’t
‘a writer’s friend,’ it is ‘my friend, WHO IS a writer.’ This no is

a special form of the copula, an alternant, or the alternate
form, of the word da that occurs whenever a copular clause

is put in the modifier position before a noun phrase. You can
see the difference between the particle no and the copula-

alternant no (= da) here:

作家の友達 sakka no the writer’s friend
tomodachi

作家の友達 sakka no the friend WHO IS a
tomodachi writer

Since the two expressions sound just alike, you have to

tell from the context or situation which no it is you are
hearing. Most of the time, there is little doubt. Here are

additional examples:

母親が６０歳以上の学生は全体の３０％だった。

Hahaoya ga rokujus-sai ijō no gakusei wa zentai no
sanjup-pāsento datta.
The students whose mothers are over sixty

years old constituted 30 percent of entire
student body.

うちの会社には出身が九州の男性が３人いる。
Uchi no kaisha ni wa shusshin ga Kyūshū no dansei ga

san-nin iru.