～は～だ (copula)

• Reading: は
• Romaji: wa
• Formation: Topic + は + Noun/Na-adjective + だ/です

Meaning

The most fundamental sentence pattern in Japanese. は marks the topic of the sentence, and だ (or its polite form です) functions as the copula, equivalent to English 'is,' 'am,' or 'are.' This structure is used to identify, describe, or classify the topic.

This pattern forms the backbone of Japanese sentence construction. は (pronounced 'wa' when used as a particle) marks the topic — what the sentence is about — while だ/です asserts something about that topic. Unlike English, the copula does not change for person or number: 私はAだ and 彼はAだ use the same form. です is simply the polite equivalent of だ and is preferred in formal or neutral speech. Beginners often confuse は with が; は sets the topic (known information), while が marks the subject (often new information). When the predicate is an い-adjective, だ is typically omitted in plain form.

Examples

1. 私は大学生です。 I am a university student.
2. 東京は日本の首都だ。 Tokyo is the capital of Japan.
3. この料理はとてもおいしいです。 This dish is very delicious.

Usage Guide

Context: spoken, written, everyday

Tone: descriptive

Do Say

• 今日は天気がいいですね。
• 私は毎朝コーヒーを飲みます。
• この本は面白いです。
• 姉は看護師です。

Don't Say

• 私が学生です。(Using が instead of は when introducing yourself as a topic) → 私は学生です。
• 彼女は優しいだです。(Adding だ before です creates a grammatical error) → 彼女は優しいです。
• この映画は面白いだ。(Adding だ after an い-adjective is incorrect) → この映画は面白い。

Origin & History

は derives from the Old Japanese bound particle 'pa,' which evolved phonetically into 'wa' in the Heian period. だ developed from the copula 'de aru' through contraction.

Cultural Context

Generation: All ages

Social background: Universal