“de wa nai ka / ja nai ka” Meaning — Isn't It…? / …, Right! [JLPT N3]
Content by NTJ Kuma · Nihongo to Japan editorial team · Updated July 27, 2026
“That's amazing, isn't it!” — confirming, marveling, or rhetorically questioning, with examples. (JLPT N3)
「やればできるじゃないか！」 — 「じゃないか」, tossing a judgment to the other with feeling
「ほら、やればできるじゃないか！」 (see, you can do it if you try!) — 「(plain form) ＋ ではないか／じゃないか」 tosses your view or judgment to the other for confirmation, with feeling. It has several feels: ① assertion, rhetorical question (isn't it…?); ② discovery, exclamation (why, it's…!); ③ reproach (isn't this…?). 「じゃないか」 is the colloquial version of 「ではないか」. This guide covers this emotive pattern and separates it from 「だろう」.
Core: toss your judgment to the other, with feeling
「ではないか／じゃないか」 = tossing a judgment to the other with feeling (seeking their agreement/confirmation):
- ① Assertion, rhetorical question (isn't it…?, right?): これは君のミスじゃないか (isn't this your mistake?).
- ② Discovery, exclamation (why, it's…!): やればできるじゃないか (you can do it after all!), すごいじゃないか (that's amazing!).
- ③ Warning, reproach: 危ないじゃないか (that's dangerous, isn't it).
Feel: emotional (praise, reproach, realization), not a neutral question.
How to Connect
| Form | Use | Example |
|---|---|---|
| plain form ＋ じゃないか | assertion/rhetorical | 君のミスじゃないか |
| 〜じゃないか (exclamation) | discovery, praise | できるじゃないか |
| ではないか (written/weighty) | more formal | 問題あるではないか |
實用例句
- ほら、やればできるじゃないか！(See, you can do it if you try!) — discovery, encouragement
- これ、君のミスじゃないか。(Isn't this your mistake?) — reproach
- おお、すごいじゃないか！(Oh, that's amazing!) — praise
- 危ないじゃないか、気をつけろ。(That's dangerous — be careful.) — warning
- いい考えじゃないか。やってみよう。(That's a good idea, isn't it. Let's try it.) — agreement
⚠️ Where learners slip up
① Don't add 「だ／でしょう」 after. すごいじゃないか (✗ すごいじゃないかだ, ✗ じゃないかでしょう). 「じゃないか」 is already sentence-final; nothing follows.
② It carries “feeling,” not a neutral question. 「じゃないか」 isn't a plain “is it…?” — it tosses “I think it's…” with praise/reproach/realization (できるじゃないか = (I told you) you can do it, with encouragement/realization). For a neutral question, use 「〜ですか」.
③ 「じゃないか」 (colloquial, casual, leans masculine) vs 「ではないか」 (written, weighty). Daily, emotional speech uses 「じゃないか」 (「じゃん」 is even more casual); formal, written, weighty assertions use 「ではないか」 (〜のではないか = might it be…?, a softened assertion).
🔄 Compare with similar forms: じゃないか／だろう／よね
| Form | Nuance | Example |
|---|---|---|
| 〜じゃないか | tosses a judgment with feeling (praise/reproach/realization) | できるじゃないか |
| 〜だろう | guess, confirm (probably) | できるだろう |
| 〜よね | seek agreement, confirm | できるよね |
💡 The one thing to remember
「じゃないか（ではないか）」 is a very emotive line — not a neutral question, but tossing “I think it's…” with praise, reproach, or realization. Three common scenes: ① discovery, encouragement (やればできるじゃないか = (see) you can do it, with realization/encouragement); ② praise (すごいじゃないか = that's amazing); ③ reproach, warning (危ないじゃないか = that's dangerous). Speech uses 「じゃないか」 (even more casual 「じゃん」); written/weighty uses 「ではないか」. One reminder: don't add だ/でしょう after. To emotionally “toss a judgment and seek agreement,” this line is vivid. For a softened assertion, use 「〜のではないか (might it be…?)」.
❓ Quick FAQ
Q: How do I tell 「じゃないか」 from 「だろう」?
By whether there's “feeling.” 「じゃないか」 = tossing a judgment with feeling (praise, reproach, realization), seeking agreement: できるじゃないか！ ((see) you can do it! — encouragement/realization), 君のミスじゃないか (isn't this your mistake? — reproach). 「だろう」 = a (more neutral) guess, confirmation (probably…): 明日は晴れるだろう (it'll probably clear up tomorrow — guess), できるだろう (you can probably do it — guess). So 「じゃないか」 carries strong feeling and “tosses” the judgment to the other; 「だろう」 is more neutral, just a guess or confirmation. For praise/reproach use じゃないか, for a plain guess use だろう.
Q: What's the difference between 「じゃないか」 and 「ではないか」?
Same meaning, differing in register. 「じゃないか」 = colloquial, casual (daily speech, emotional, leaning masculine; even more casual is 「じゃん」: すごいじゃん). 「ではないか」 = written, weighty (formal settings, speeches, writing). Also, 「〜のではないか／〜のではないだろうか」 is a common pattern for softly asserting your view (それは違うのではないか = might that not be wrong? — a gentle challenge), more polite than a blunt 「違う」. So: everyday emotional exclamation/reproach → 「じゃないか」; a formal, softened assertion → 「（の）ではないか」.
🖊️ Practice Questions (5)
Q1. 「やればできる___。自信を持って。」(you can do it if you try, right? — encouraging)
(A) じゃないか (B) ものか (C) どころか (D) ばかり
Q2. 「これ、君のミス___。」(isn't this your mistake? — questioning)
(A) ではないか (B) に違いない (C) かもしれない (D) はずがない
Q3. 「すごいじゃないか！」が表すのは?
(A) Surprise / admiration (that's amazing!)
(B) A command
(C) Doubt / uncertainty
(D) Refusal
Q4. 「じゃないか」と「ではないか」の違いは?
(A) じゃないか = colloquial; ではないか = more written / formal
(B) The meanings are exact opposites
(C) じゃないか = written
(D) ではないか = children's speech
Q5. 用法が自然なのは?
(A) もっと早く言えばよかったじゃないか。 (B) 行くじゃないかでしょう。
(C) 雨じゃないかだ。 (D) 高いじゃないかにちがいない。
Answer Explanations
1. (A) じゃないか ── Encouragement: "you can do it, can't you".
2. (A) ではないか ── Questioning an assertion.
3. (A) ── Surprise / admiration.
4. (A) ── じゃないか colloquial; ではないか written.
5. (A) ── (A) is natural (with reproach/regret); the other connections are wrong.