# てはならない: must not

> Learn how to use てはならない, a JLPT N2 Japanese grammar point meaning must not, with structure, nuance, examples, mistakes, and comparisons.

JLPT level: N2 · Updated: 2026-05-06 · Canonical: https://hane-app.com/blog/n2-tewa-naranai/

**てはならない** means **must not**. It is a **JLPT N2** Japanese grammar pattern used to **state a prohibition in a formal or strict way**.

This grammar point often appears in advanced reading, formal writing, notices, essays, and careful conversation. If you want to read Japanese with more nuance, **てはならない** is a useful pattern to learn because it shows the speaker's logic, stance, or emphasis.

## What does てはならない mean?

Use **てはならない** when you want to **state a prohibition in a formal or strict way**.

Natural translations include:
- must not
- depending on context
- in a way that matches the speaker's emphasis

The best translation depends on the sentence. Focus first on what relationship the pattern creates between the ideas.

## How to form てはならない

Verb て-form + はならない

Examples of the pattern:
- 個人情報を外部に漏らしてはならない。
- 試験中に話してはならない。
- この事実を忘れてはならない。

In JLPT questions, pay close attention to the word immediately before the grammar point. Many wrong answers use a similar meaning but attach to the wrong form.

## When is てはならない used?

Use **てはならない** in situations like:
- reading formal explanations, announcements, or essays
- making a point more precise than a basic grammar pattern would
- connecting two ideas with a clear nuance

Tone and register:
- usually neutral to formal, depending on the expression
- common in JLPT N2 reading passages, news, notices, and business-like writing

## てはならない example sentences

- 個人情報を外部に漏らしてはならない。 — Personal information must not be leaked outside.
- 試験中に話してはならない。 — You must not talk during the exam.
- この事実を忘れてはならない。 — We must not forget this fact.
- 安全確認を怠ってはならない。 — Safety checks must not be neglected.
- 他人の努力を笑ってはならない。 — You must not laugh at another person's effort.

After reading each sentence, ask what job **てはならない** is doing. Is it adding, excluding, warning, emphasizing, or showing a condition? That habit makes the nuance easier to remember than a single English translation.

## Nuance of てはならない

The key nuance is **state a prohibition in a formal or strict way**.

This matters because N2 grammar often overlaps with easier expressions. The advanced pattern usually adds formality, emphasis, restriction, or a stronger logical relationship.

For example:
- In formal writing, **てはならない** often sounds more precise than a casual equivalent.
- Compared with **てはいけない**, it has a different tone or scope even when the English translation looks similar.

## てはならない vs てはいけない

Both **てはならない** and **てはいけない** can express related ideas, but they are different.

**てはならない**:
- fits the N2 nuance explained above
- often sounds more specific, formal, or emphatic

**てはいけない**:
- is usually broader, simpler, or used in a different register
- may be better in casual conversation depending on the sentence

Quick contrast examples:
- 個人情報を外部に漏らしてはならない。
- Try rewriting the sentence with **てはいけない** and notice whether the tone or meaning changes.

## Common mistakes with てはならない

Watch out for these mistakes:
- Translating it too literally and missing the function in context
- Confusing it with **てはいけない** just because the English translation overlaps
- Using it in casual speech when a simpler pattern would sound more natural

A helpful practice method is to write one sentence with **てはならない**, then compare it with a related grammar point. Explain the difference in your own words.

## Is てはならない on the JLPT?

Yes. **てはならない** is commonly taught as **JLPT N2** grammar.

That means learners should be able to:
- recognize it in reading
- understand its nuance in context
- use it in simple original sentences

For test preparation, study the grammar point in full sentences. JLPT questions usually test context, not dictionary translation alone.

## Practice questions for てはならない

Try making your own sentences with these prompts:
- Write one sentence that clearly needs **てはならない**.
- Write a second sentence with **てはいけない** and compare the nuance.
- Find a notice, article, or dialogue where this kind of meaning would be natural.

## Learning path for てはならない

To learn **てはならない** efficiently, follow a path that matches this pattern's real function.

1. First review the formation so the base structure feels natural.
2. Then compare **てはならない** with **てはいけない** and the related lessons below. These recommendations are chosen from similar semantic or structural families.
3. Finally, write your own sentence where the context makes **てはならない** necessary.

## Related grammar to review next

- [n5 te wa ikenai](/blog/n5-te-wa-ikenai/) — review this next because it is close in meaning, form, or register
- [n2 neba naranai](/blog/n2-neba-naranai/) — review this next because it is close in meaning, form, or register
- [n4 na](/blog/n4-na/) — review this next because it is close in meaning, form, or register

## Learn てはならない with Hane

If you want to review **てはならない** together with the related patterns above, Hane helps you connect grammar, kanji, and vocabulary in short, focused sessions.

Browse more lessons here:
- [All grammar lessons](/blog/)
- [JLPT N2 grammar lessons](/blog/n2/)