# ではないか: isn’t it; don’t you think

> Learn how to use ではないか, a JLPT N4 Japanese grammar point meaning isn’t it; don’t you think, with structure, nuance, examples, mistakes, and comparisons.

JLPT level: N4 · Updated: 2026-05-17 · Canonical: https://hane-app.com/blog/n4-dewa-nai-ka/

**ではないか** means **isn’t it; don’t you think**. It is a **JLPT N4** Japanese grammar pattern used to seek confirmation or make an emphatic realization.

This grammar point often appears in conversation, written explanations, formal notices, and JLPT-style reading questions. If you want to seek confirmation or make an emphatic realization, **ではないか** is a useful pattern to learn after the N5 basics.

## What does ではないか mean?

Use **ではないか** when you want to seek confirmation or make an emphatic realization.

Natural translations include:
- isn’t it
- right
- isn’t it; right

The exact English translation changes with context. Focus on what the grammar point does in the sentence first, then choose the English phrase that sounds natural.

## How to form ではないか

<div class="formation">
  <div class="formula">
    <span class="ftoken">Plain statement</span> <span class="fplus">+</span> <span class="ftoken t-core">ではないか</span>
  </div>
</div>

Examples of the pattern:
- 便利ではないか
- いいではないか
- 学生ではないか

Pay attention to the word form before the pattern. Many JLPT N4 mistakes happen because the meaning is understood, but the grammar is attached to the wrong form.

## When is ではないか used?

Use **ではないか** in situations like:
- explaining a condition, reason, decision, or time relationship
- making a sentence more specific than a basic N5 pattern
- understanding natural Japanese in conversation or reading

Tone and register:
- neutral unless the grammar itself is marked as casual, humble, honorific, or formal
- Common in daily speech, textbook examples, and JLPT N4 reading questions

## ではないか example sentences

<div class="examples">
  <div class="example">
    <div class="example-jp">これは<ruby>便利<rt>べんり</rt></ruby>ではないか。</div>
    <div class="example-en">This is convenient, isn’t it?</div>
    <div class="example-foot"><span class="example-tag">na-adj</span></div>
  </div>
  <div class="example">
    <div class="example-jp"><ruby>彼<rt>かれ</rt></ruby>は<ruby>学生<rt>がくせい</rt></ruby>ではないか。</div>
    <div class="example-en">He is a student, isn’t he?</div>
    <div class="example-foot"><span class="example-tag">noun</span></div>
  </div>
  <div class="example">
    <div class="example-jp">いい<ruby>考<rt>かんが</rt></ruby>えではないか。</div>
    <div class="example-en">That is a good idea, isn’t it?</div>
    <div class="example-foot"><span class="example-tag">i-adj</span></div>
  </div>
  <div class="example">
    <div class="example-jp">もう<ruby>時間<rt>じかん</rt></ruby>ではないか。</div>
    <div class="example-en">It is already time, isn’t it?</div>
    <div class="example-foot"><span class="example-tag">noun</span></div>
  </div>
  <div class="example">
    <div class="example-jp">この<ruby>方法<rt>ほうほう</rt></ruby>でできるではないか。</div>
    <div class="example-en">We can do it this way, can’t we?</div>
    <div class="example-foot"><span class="example-tag">verb</span></div>
  </div>
</div>

Read the Japanese sentence first, then check the English translation. Try to notice what the grammar point contributes: condition, timing, limitation, possibility, decision, politeness, or emphasis.

## Nuance of ではないか

The key nuance is **sounds less contracted and more formal**.

This matters because **ではないか** may look simple in English, but the Japanese form tells you whether the speaker is describing a time, a condition, a decision, a possibility, or a social relationship.

For example:
- In context, **ではないか** helps make the sentence more precise than a direct English translation. 
- Compared with **じゃないか**, it has a different focus even when both patterns appear in similar sentences.

## ではないか vs じゃないか

Both **ではないか** and **じゃないか** can appear in related sentences, but they are different.

<div class="compare">
  <div class="cmp">
    <div class="cmp-head a">ではないか</div>
    <div class="cmp-sub">Formal, less contracted</div>
    <div class="cmp-when">Use in formal speaking, writing, and polite contexts.</div>
    <div class="cmp-eg">これは<ruby>便利<rt>べんり</rt></ruby>ではないか。</div>
    <div class="cmp-eg-en">This is convenient, isn’t it?</div>
  </div>
  <div class="vs">vs</div>
  <div class="cmp">
    <div class="cmp-head b">じゃないか</div>
    <div class="cmp-sub">Casual, contracted</div>
    <div class="cmp-when">Use in casual conversation and informal contexts.</div>
    <div class="cmp-eg">これは<ruby>便利<rt>べんり</rt></ruby>じゃないか。</div>
    <div class="cmp-eg-en">This is convenient, isn’t it?</div>
  </div>
</div>

If you are unsure which one to use, identify the main job of the sentence before translating it into English.

## Common mistakes with ではないか

<div class="mistakes">
  <div class="mistake">
    <div class="mline">
      <div class="mark bad">❌</div>
      <div class="mline-body">Attaching to the wrong form, like <span class="bad">便利だではないか</span>.</div>
    </div>
    <div class="mline">
      <div class="mark good">✅</div>
      <div class="mline-body">Attach directly to the plain form: <span class="good">便利ではないか</span>.</div>
    </div>
  </div>
  <div class="mistake">
    <div class="mline">
      <div class="mark bad">❌</div>
      <div class="mline-body">Using <span class="bad">じゃないか</span> in formal writing where <span class="good">ではないか</span> is expected.</div>
    </div>
    <div class="mline">
      <div class="mark good">✅</div>
      <div class="mline-body">Match register to context: <span class="good">ではないか</span> for formal, <span class="good">じゃないか</span> for casual.</div>
    </div>
  </div>
  <div class="mistake">
    <div class="mline">
      <div class="mark bad">❌</div>
      <div class="mline-body">Translating word-for-word without reading the full sentence context.</div>
    </div>
    <div class="mline">
      <div class="mark good">✅</div>
      <div class="mline-body">Read the whole sentence to confirm whether the speaker is seeking agreement or making a realization.</div>
    </div>
  </div>
</div>

A good study habit is to write one short sentence and then change only the grammar point. This makes the difference between similar patterns easier to feel.

## Is ではないか on the JLPT?

<div class="jlpt-card">
  <div class="jlpt-shield">N4</div>
  <div class="jlpt-info">
    <div class="jlpt-checks">
      <p>Yes. <strong>ではないか</strong> is commonly taught as <strong>JLPT N4</strong> grammar.</p>
      <p>That means learners should be able to:</p>
      <ul>
        <li>recognize it in reading</li>
        <li>understand its nuance in context</li>
        <li>use it in simple original sentences</li>
      </ul>
      <p>For test preparation, do not only memorize the English gloss. Practice identifying the words around the grammar point, because JLPT questions often test structure and context together.</p>
    </div>
  </div>
</div>

## Practice questions for ではないか

<div class="prompts">
  <div class="prompt">
    <span class="prompt-num">1</span>
    <span class="prompt-text">Write one sentence using the basic pattern.</span>
    <span class="prompt-tag">production</span>
  </div>
  <div class="prompt">
    <span class="prompt-num">2</span>
    <span class="prompt-text">Change the sentence into polite or casual style if possible.</span>
    <span class="prompt-tag">variation</span>
  </div>
  <div class="prompt">
    <span class="prompt-num">3</span>
    <span class="prompt-text">Compare ではないか with じゃないか in your own example.</span>
    <span class="prompt-tag">comparison</span>
  </div>
</div>

Keep the sentences short at first. Once the form feels natural, add time words, places, reasons, or contrast to make the sentence more realistic.

## Learning path for ではないか

<div class="path">
  <div class="path-step">
    <span class="step-num">1</span>
    <div class="step-body">Make sure you can form <strong>ではないか</strong> by attaching it to a plain statement without the copula <strong>だ</strong>.</div>
  </div>
  <div class="path-step">
    <span class="step-num">2</span>
    <div class="step-body">Compare <strong>ではないか</strong> with <strong>じゃないか</strong> to feel the register difference.</div>
  </div>
  <div class="path-step">
    <span class="step-num">3</span>
    <div class="step-body">Practice with different subjects, time expressions, and adjective types to build flexibility.</div>
  </div>
  <div class="path-step">
    <span class="step-num">4</span>
    <div class="step-body">Review alongside related N4 patterns like <a href="/blog/n4-nowa-da/">のは〜だ</a> and <a href="/blog/n4-to-omou/">と思う</a> to see how sentence boundaries and nuance shift.</div>
  </div>
</div>

## Related grammar to review next

- [のは〜だ](/blog/n4-nowa-da/) — builds control over quoted thoughts, questions, names, and explanations.
- [と言ってもいい](/blog/n4-to-ittemo-ii/) — builds control over quoted thoughts, questions, names, and explanations.
- [と思う](/blog/n4-to-omou/) — builds control over quoted thoughts, questions, names, and explanations.
- [という](/blog/n4-to-iu/) — builds control over quoted thoughts, questions, names, and explanations.

## Learn ではないか with Hane

If you want to review **ではないか** together with the related patterns above, Hane helps you practice Japanese in short, focused sessions.

Browse more lessons here:
- [All grammar lessons](/blog/)
- [JLPT N4 grammar lessons](/blog/n4/)