Grammar Info

N2 Lesson 1: 14/23


Just in case, In the worst-case scenario, In the unlikely event, By any chance

Can have a negative connotation


(まん)(いち) + Phrase


  • Register


  • 使用域


About 万が一

(まん)(いち), or sometimes simply 万一(まんいち) is a grammar pattern that literally means '1 in 10000'. It is used in a similar way to phrases such as 'in the unlikely event of (A)', or 'just in case (A)' in English, and will usually highlight some measure against (A), or what will happen as a result of (A) in the latter half of the sentence.
(まん)(いち) is primarily used adverbially, so will often come at the beginning of sentences.
  • (まん)(いち)(とき)のために防災(ぼうさい)セットを()っておきましょう。
    Let's buy a disaster kit (in advance) just in case.
  • (まん)(いち)()れなくなった場合(ばあい)は、連絡(れんらく)をください。
    In the unlikely event that you are unable to come, please contact us.
Fun-fact - (まん)(いち) is considered slightly stronger than 万一(まんいち), but (まん)(いち) is far more common due to it being easier to pronounce.
  • (まん)(いち)(とき)のためにメールアドレスも(おし)えていただいてもよろしいでしょうか。
    Can I possibly have your email address too just in case.
  • 万一(まんいち)()からないことがあれば、(なん)でも(わたし)()いてください。
    If by chance, there is something you don't understand, you can ask me anything.



  • (まん)(いち)のことがあったら、祖母(ばあ)さん(いえ)()どもを(あず)けることになっている。

    If an unlikely event happens, it has been decided that the children will be entrusted to grandmother.

    • (まん)(いち)(たから)くじが()たったら、世界(せかい)一周(いっしゅう)旅行(りょこう)する(おも)

      By any chance, if I win a lottery, I think I will go on a round-the-world trip.

      • (まん)(いち)のために、消火器(しょうかき)()ことにした。

        I decided to buy a fire extinguisher, just in case.

        • (まん)(いち)(おも)いついたら、アイデアを(おし)えてください。

          Just in case you think of something, please tell me your idea.

          • (まん)(いち)(くま)足跡(あしあと)()つけた場合(ばあい)は、連絡(れんらく)してください。

            Just in case you should find bear tracks, please let me know.

            • Get more example sentences!

              Premium users get access to 12 example sentences on all Grammar Points.

            Self-Study Sentences

            Study your own way!

            Add sentences and study them alongside Bunpro sentences.

            • Online

            • Offline

              There are no Offline resources listed for 「万が一」.

              You can . Resources are constantly updated, come back later to see new additions!

            • Track Resources!

              Bunpro tracks all of the resources you’ve visited, and offers relevant bookmarks of physical books to help with offline tracking.

            万が一 – Grammar Discussion

            Most Recent Replies (3 in total)

            • Brand_S


              I’ve noticed that 万一 often appears in the phrase 万一に備える, to mean to provide against contingencies. Is that true of 万が一 as well?

            • Fuga


              Hey there!

              万一 is just a short 万が一 with the が omitted, so both would work with that phrase! I hope that answers your question!

            • Brand_S


              It does! Thank you! I’ve actually only ever seen 万一に備える in the wild. I didn’t know until I saw that grammar item that 万一 was still used in other contexts!

            Got questions about 万が一? Join us to discuss, ask, and learn together!

            Join the Discussion