Page 170 - Basic Japanese

-ii like ōkii is big

They are inflected simply by adding certain endings to
the vowel before the -i, which is the imperfect ending itself:

Imperfect Perfect Gerund Infinitive

-i -katta -kute -ku

The copula is somewhat irregularly inflected, so the

forms are best learned as separate words rather than being
broken into stem and ending. The adjective ii ‘is good’ has

an alternate form yoi ‘is good.’ The other forms are all based

only on the form yoi.

Here are some examples of inflected forms of adjectives

and the copula used in sentences: