Japanese Grammar for Obligation -
Intermediate Lessons: 16

In the previous lesson, you have learned the Japanese grammar on permission (you may do something) and prohibition (you must not do something). In this lesson, you will learn grammar on obligation (you must do something) and no obligation (you don't have to do something).

It's always much easier to understand the grammar with the sentence patterns than to explain in plain words.

Verb (ない-form ない) なくてもいいです No Obligation
Verb (nai-form nai) nakutemo ii desu You don't have to do ~/
You need not do ~
Verb (ない-form ない) なければいけません Obligation 義務 (gimu)
Verb (nai-form nai) nakereba ikemasen You have to do ~/You must do ~

The two grammars are formed by using ない-form (nai-form).

Although the grammar Verb (ない-form ない) なければいけません is in negative form (~ません), its meaning is positive (you have to do ~).

On the contrary, though the grammar Verb (ない-form ない) なくてもいいです is in positive form (~です), its meaning is negative (you don't have to do ~).

Let's take a look at some examples...

Japanese Grammar Obligation

  1. 早くおきなければいけません。
    hayaku okinakereba ikemasen
    Meaning: You have to get up early.
    早く起きなくてもいいです。
    hayaku okinakutemo ii desu
    Meaning: You don't have to get up early.

  2. 学校へ行かなければいけません。
    gakkou e ikanakereba ikemasen
    Meaning: You have to go to school.
    学校へ行かなくてもいいです。
    gakkou e ikanakutemo ii desu
    Meaning: You don't need to go to shcool.

  3. 宿題をしなければいけません。
    shukudai wo shinakereba ikemasen
    Meaning: You have to do homework.
    宿題をしなくてもいいです。
    shukudai wo shinakutemo ii desu
    Meaning: You don't have to do homework.

  4. 朝薬を飲まなければいけません。
    asa kusuri wo nomanakereba ikemasen
    Meaning: You have to take the medicine in the morning.
    夜薬を飲まなくてもいいです。
    yoru kusuri wo nomanakutemo ii desu
    Meaning: You don't need to take the medicine in the evening.

Questions and Answers in Japanese Grammar for Obligation

How do you ask a question whether you need to do something? And how do you answer the question? I think you should have known the answer. It's easy, right? Just add the question word か (ka) to the Japanese grammar. Since this is a Yes/No question, the answer should begin with はい (hai) or いいえ (iie).

For positive meaning,
Verb (ない-form ない) なければいけません - I have to do something.
Verb (ない-form ない) なければいけませんか - Do I have to do something?

The sentence patterns for positive questions and answers will be...

Question: Verb (ない-form ない) なければいけませんか
Do I have to do something?
Answer Yes: はい、Verb (ない-form ない) なければいけません
Yes you have to do...
Answer No: いいえ、Verb (ない-form ない) なくてもいいです
No you don't have to do...

For negative meaning,
Verb (ない-form ない) なくてもいいです - I don't have to do something.
Verb (ない-form ない) なくてもいいですか - Don't I have to do something?

The sentence patterns for negative questions and answers will be...

Question: Verb (ない-form ない) なくてもいいですか
Don't I have to do something?
Answer No: はい、Verb (ない-form ない) なくてもいいです
No you don't have to do...
Answer Yes: いいえ、Verb (ない-form ない) なければいけません
Yes you have to do...

Note: There are differences in the Japanese answers and the English translations.

As mentioned in the last lesson, "はい (hai)" in Japanese actually means "I agree with what you said" and not simply a direct translation of "Yes" in English. Similarly, "いいえ (iie)" means "I disagree with what you said" and not directly translated to "No" in English. Therefore there are differences in the Japanese answers and the English translations when you answer "Yes" or "No" to a negative question.

Examples for Questions and Answers in Japanese Grammar for Obligation

Let's use an example to explain both the positive and negative questions and answers for this Japanese grammar.

For positive questions and answers...

    Question: 漢字で書かなければいけませんか。
    kanji de kakanakereba ikemasen ka
    Meaning: Do I have to write in Kanji?
    Answer Yes: はい、漢字で書かなければいけません。
    hai, kanji de kakanakereba ikemasen
    Meaning: Yes, you have to write in Kanji.
    Answer No: いいえ、漢字で書かなくてもいいです。
    iie, kanji de kakanakutemo ii desu
    Meaning: No, you don't have to write in Kanji.

For negative questions and answers...

    Question: 漢字で書かなくてもいいですか。
    kanji de kakanakutemo ii desu ka
    Meaning: Don't I have to write in Kanji?
    Answer No: はい、漢字で書かなくてもいいです。
    hai, kanji de kakanakutemo ii desu
    Meaning: No, you don't have to write in Kanji.
    Answer Yes: いいえ、漢字で書かなければいけません。
    iie, kanji de kakanakereba ikemasen
    Meaning: Yes, you have to write in Kanji.

When Answering to Superiors/Customers

The tone is too strong when you are answering with Verb (ない-form ない) なければいけません - "You have to do something / You must do something". It's normally used by parents to children or teachers to students. If you are answering to your superiors, boss or customers, it sounds too rude.

Therefore when answering to your superiors, boss or customers, you will normally use the Japanese grammar in request form "Verb (て-form) ください" to be more polite. In the previous example, use 書いてください (kaite kudasai) to replace 書かなければいけません (kakanakereba ikemasen) to make it more polite.

When to ask Positive Question or Negative Question?

Both positive question and negative question will be used depending on situation.

For example, in a test, everyone is using pencil to write one's answers except you, who want to use pen. In this situation, what would you ask your teacher?

  1. Positive: 鉛筆で書かなければいけませんか。 (enpitsu de kakanakereba ikemasen ka)
    Meaning: Do I have to write in pencil?

    OR

  2. Negative: 鉛筆で書かなくてもいいですか。 (enpitsu de kakanakutemo ii desu ka)
    Meaning: Don't I have to write in pencil?

In this situation, it seems like you have to use pencil since everyone is using pencil. Therefore you should ask the positive question "鉛筆で書かなければいけませんか。 - Do I have to write in pencil?"

After the test, when you submit your paper to your teacher, you saw that no one has written his/her name on the test paper except you. Everyone only wrote down his/her serial number. You are surprised. You thought you must write your name and serial number on the test paper. In this situation, what should you ask your teacher?

  1. Positive: 名前を書かなければいけませんか。 (namae wo kakanakereba ikemasen ka)
    Meaning: Do I have to write my name?

    OR

  2. Negative: 名前を書かなくてもいいですか。 (namae wo kakanakutemo ii desu ka)
    Meaning: Don't I have to write my name?

In this situation, it seems like it's not required to write your name on the test paper since everyone only wrote his/her serial number. Therefore you should ask the negative question "名前を書かなくてもいいですか。 - Don't I have to write my name?"

Difference between なければいけません and なければなりません

Verb (ない-form ない) なければいけません Obligation 義務 (gimu)
Verb (nai-form nai) nakereba ikemasen You have to do ~/You must do ~
Verb (ない-form ない) なければなりません Obligation 義務 (gimu)
Verb (nai-form nai) nakereba narimasen You have to do ~/You must do ~

In general, you can use either of the Japanese grammars as both of them have the same meaning. However, native Japanese use them with slight difference.

For ~なければいけません (~nakereba ikemasen) - you want to do something and you think that you have to do it.

For ~なければなりません (~nakereba narimasen) - you don't want to do something but you have no choice and have to do it. So normally, this is used when you want to make excuses.

For example, your friend invites you to go for dinner with him/her. You can say the following...

  • すみません。明日は試験だから、今晩勉強しなければなりません。
    sumimasen. ashita wa shiken da kara, konban benkyou shinakereba narimasen
    Meaning: I am sorry. There is an exam tomorrow, therefore I have to study tonight.

In fact, the Japanese grammar ~なければなりません (~nakereba narimasen) is more commonly used by native Japanese than ~なければいけません (~nakereba ikemasen).

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