じゃないかjanai ka“right; isn’t it”

じゃないか (janai ka) looks like a negative question, but it isn’t one. Said with a falling tone, it means “hey, it’s ~!”, “see, ~!”, or “I told you ~!” The speaker is pointing at something they think is obvious: ここにあるじゃないか — “It’s right here!”

It is a JLPT N4 pattern of spoken Japanese, the casual counterpart of ではないか. You hear it in anime, dramas and everyday speech whenever someone discovers something, praises someone, or reminds them of something they should have known.

じゃないか doesn’t ask if something is true. It says “look, it’s true, can’t you see?”

What does じゃないか mean?

Literally, じゃないか is “isn’t it ~?” In use, the speaker already knows the answer and wants the listener to agree or notice. It has four main jobs:

• Discovery or surprise: あれ、田中じゃないか！ — Hey, it’s Tanaka!
• Reminding or blaming: 言ったじゃないか。 — I told you!
• Praise, often a little surprised: やればできるじゃないか。 — See, you can do it when you try!
• Rallying (with the volitional): 行こうじゃないか。 — Come on, let’s go!

With の／ん in front, the meaning shifts to a cautious guess: 雨が降るんじゃないか — “I think it might rain.” That use is covered in the nuance section below.

How to form じゃないか

じゃないか follows the plain form. Nouns and な-adjectives drop だ; verbs and い-adjectives attach directly.

The same idea comes in several politeness levels:

• ではないか — written, formal, or dignified speech
• じゃないか — spoken, casual; sounds a little masculine or older
• じゃない↘ — casual and neutral; very common among women and younger speakers
• じゃん — very casual, especially in Tokyo-area speech
• じゃないですか — polite, but it can sound pushy (“as you surely know”)

When is じゃないか used?

• Spotting something: finding lost keys, running into a friend, noticing the time.
• Scolding or reminding: 気をつけてって言ったじゃないか — the speaker insists the listener should have known.
• Encouraging or praising: a coach, parent, or teacher reacting to good work: 上手じゃないか.
• Speeches and slogans: 〜しようじゃないか calls a group to action, in a rousing, slightly old-fashioned tone.

Always say it with a falling tone. With a rising tone, the same words become a real negative question (“isn’t it…?”).

じゃないか example sentences

In examples 1 to 5 the speaker already knows the answer. None of them is really a question, which is why the English uses “hey,” “see,” or an exclamation mark.

Nuance of じゃないか

The core feeling is “this should be obvious to you.” That makes the tone depend on context. When the obvious thing is good news (おいしいじゃないか), it sounds warm and pleasantly surprised. When it is something the listener should have remembered (言ったじゃないか), it sounds like a reproach.

Because it pushes the listener toward agreement, じゃないか is not for people above you. To your boss, even じゃないですか can sound like “as you should know.” Use よね or ですよね instead: 昨日そうおっしゃいましたよね.

んじゃないか is different. Adding ん (or の) turns “look, it’s X!” into “I suspect X.” The speaker is no longer sure; they are offering a guess: 田中さんはもう帰ったんじゃないか — “I think Tanaka has probably already gone home.” This is close to だろう and often more natural in conversation.

💡 Gender and age: じゃないか sounds slightly rough and male. Many speakers, especially women, say じゃない↘ or じゃん for the same meaning. In reading, じゃないか often signals a male character.

じゃないか vs ではないか

These have the same meanings and the same grammar. The difference is register.

If you are talking, use じゃないか (or じゃない / じゃん). If you are writing a report or essay, use ではないか. Switching between them never changes the meaning.

Common mistakes with じゃないか

Is じゃないか on the JLPT?

A common listening trap: someone says 「この店、安いじゃない」 with a falling tone. It means the shop is cheap, not that it isn’t.

Practice questions for じゃないか

Learning path for じゃないか

Related grammar to review next

• ではないか — the formal, written version with the same meanings.
• じゃない / ではない — the plain negative that じゃないか is built from.
• だろう — “probably,” close in meaning to the guessing んじゃないか.
• ね — the softer way to invite agreement.
• 意向形 (volitional form) — needed for the “let’s ~ じゃないか” call to action.

Learn じゃないか with Hane

Hane plays じゃないか, じゃない and じゃん in short dialogues, so you learn to hear the falling “see, it’s obvious” tone. Train your ear in Hane.