てはならないtewa naranai“must not”

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

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。

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.

Nuance of てはならない

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

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

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

Practice questions for てはならない

• 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.
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 — must not; may not.
• n2 neba naranai — must; have to.
• n4 na — do not do; prohibition.

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
• JLPT N2 grammar lessons