Learn Hardcore Japanese: kono eiga ha kowai desu.

は is the topic marker. It signals that この映画 is what we’re talking about. Historically, this particle was pronounced “wa,” and that pronunciation remains even though it’s written with the hiragana は.

Why is は used here instead of が?

が marks the subject or introduces new information. は, by contrast, marks the topic or known information and can also imply contrast. In “この映画は怖いです,” we’re stating something about “this movie” as an established topic.

What does この do in この映画?

この is a demonstrative adjective meaning “this.” It directly modifies the noun 映画 (movie), specifying which movie we’re talking about.

Why is 怖い not followed by a copula like だ before です?

怖い is an -i adjective, which can directly serve as a predicate without needing だ. Adding です after an -i adjective simply makes the sentence polite; it doesn’t change the adjective’s form.

What role does です play after 怖い?

です is a polite sentence-ending particle (often called the copula). When you append です to -i adjectives, it doesn’t alter the adjective but raises the politeness level of the statement.

Can I omit です and still be correct?

Yes. In casual speech, you can drop です and say この映画は怖い. It means the same thing but is less formal.

How would I express “This movie was scary” or “This movie isn’t scary”?

To make past tense, change 怖い to 怖かった and add です:
この映画は怖かったです。
For negative, change -i adjective to -ku nai + です:
この映画は怖くないです。
And for past negative:
この映画は怖くなかったです。

Why is the word order この映画は before 怖いです?

Japanese generally follows a topic–comment (or SOV) order. You introduce the topic (この映画は) first, then give the comment or predicate (怖いです). In English, we use Subject–Verb–Object, but Japanese places the verb or adjective at the end.