The copula だ
Grammar: Assertion and Declaration
だ is the plain “is”. It links a noun or な-adjective to what it describes and asserts it as fact.
Usage Notes
だ conjugates: past だった, negative じゃない and ではない, conjectural だろう. Its polite counterpart is です.
Casual sentences drop だ freely, especially in questions (「元気？」) and feminine speech (「きれいね」).
Before the explanatory の it becomes な, as covered on the 〜のだ page.
Formation
- Noun ＋ だ
- 彼は高校生だ
- "He's a high school student."
- な-adjective ＋ だ
- この町は静かだ
- "This town is quiet."
- 〜だった (past)
- 昨日は休みだった
- "Yesterday was a day off."
- 〜じゃない (negative)
- 冗談じゃない
- "This is no joke."
- Dropped だ (casual)
- あれ、先生？
- "Huh, is that the teacher?"
- Note: Casual speech, questions, and feminine speech often omit だ entirely.
- Noun ＋ な ＋ の (before explanatory の)
- 猫なんだ
- "It's a cat, you see."
- Note: だ changes shape to な before the explanatory の／んだ.
Common Uses
Stating What Something Is
The plain assertion of identity or property. Yui, Sacchan, and Kotoha go on an early-morning patrol to check for any issues in their neighborhood. Because it’s so early, none of the shops are open yet, and the streets are empty.
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The Dramatic Standalone
A bare noun plus だ carries force.
だ Dropped
Casual and feminine speech leave the copula silent. Takeo runs after a mother and her child to give them a shoe they dropped. Due to Takeo’s large size and loud steps, the mother and child get frightened and run from him. After he manages to return the dropped item, Takeo returns to his friends. Rinko remarks that the scene was like “A Bear in the Forest”. Sunakawa recalls the song.
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Here, だ is omitted after やつ.Related Grammar
Supplemental Examples
