い-Adjectives and な-Adjectives
- Distinguish い-adjectives from な-adjectives by form and behavior
- Conjugate い-adjectives for the past and negative
- Describe beauty and impressions using each adjective type correctly
Two kinds of adjectives
Japanese has two adjective classes. い-adjectives end in い and conjugate like little verbs: 美しい (utsukushii, “beautiful”), 高い (takai, “tall / expensive”), 新しい (atarashii, “new”). な-adjectives (also called adjectival nouns) need な when placed before a noun: 静か (shizuka, “quiet”) → 静かな部屋 (shizuka na heya, “a quiet room”), 綺麗 (kirei, “pretty / clean”) → 綺麗な花 (kirei na hana, “a pretty flower”). Both let you describe the beauty around you, but they behave differently in grammar.
い-adjectives conjugate themselves
An い-adjective carries its own tense and negation — you do not add です for that (です only adds politeness). Present: 高い (takai, “is expensive”). Past: drop い, add かった → 高かった (takakatta, “was expensive”). Negative: drop い, add くない → 高くない (takakunai, “is not expensive”). Past negative: 高くなかった (takakunakatta). A key irregular: いい (ii, “good”) conjugates from its older stem よ- → よかった (yokatta, “was good”), not iikatta.
な-adjectives lean on です／だ
A な-adjective does not conjugate by itself; it uses the copula です／だ for tense and negation, just like a noun. 静かです (shizuka desu, “is quiet”) → past 静かでした (shizuka deshita) → negative 静かじゃありません / 静かじゃない (shizuka ja arimasen / ja nai). Before a noun it takes な (静かな町, shizuka na machi, “a quiet town”); as a predicate it drops な and uses the copula (この町は静かです, Kono machi wa shizuka desu, “this town is quiet”).
Describe a garden two ways: “This garden was beautiful” using an い-adjective, and “This garden is quiet” using a な-adjective. Show the conjugations.
- 1.“Beautiful” is 美しい (utsukushii), an い-adjective. For past tense, drop い and add かった: 美しかった (utsukushikatta).
- 2.Form the sentence with topic は: この庭は美しかったです (Kono niwa wa utsukushikatta desu). です only adds politeness; the tense is already in かった.
- 3.“Quiet” is 静か (shizuka), a な-adjective. As a present-tense predicate it uses the copula: 静かです (shizuka desu).
- 4.Form the sentence: この庭は静かです (Kono niwa wa shizuka desu).
What is the correct past-tense form of the い-adjective 高い (takai, “expensive”)?
A very common error is 高いでした for “was expensive.” い-adjectives conjugate on their own — 高かった — and you may add plain です only for politeness (高かったです). Never conjugate the adjective by changing です; change the adjective itself.
Which phrase correctly places the な-adjective 綺麗 (kirei, “pretty”) before the noun 花 (hana, “flower”)?
Watch for “trap” words that end in い but are actually な-adjectives, like 綺麗 (kirei) and 有名 (yūmei, “famous”). They do not conjugate like い-adjectives. When you learn a new descriptive word, note its type — い or な — right away.
Answer the 2 checkpoints as you read.
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