Japanese Expressions でしょう and かもしれません - Learn Japanese Online

Japanese Expressions for Guessing -
Intermediate Lessons: 11

In this lesson two Japanese expressions, でしょう (deshou) and かもしれません (kamoshiremasen) will be introduced. They are both used to indicate that the speaker is making a judgement or guess about what may possibly happen.

However there are also differences between the two of them. Let's go through them one by one.

でしょう deshou

でしょう (deshou) is normally used to express the speaker's inference or guess from some information he or she has. The sentence patterns are as follow...

Verb plain-form でしょう
い-adjective plain-form でしょう
な-adjective plain-form (~) でしょう
Noun plain-form (~) でしょう

Note: For な-adjective & noun, remove the ending だ before でしょう

For example, after looking at the dark sky, you think that it's going to rain. You can say this...

  • 空がとても暗いですから、雨が降るでしょう
    sora ga totemo kurai desu kara, ame ga furu deshou

    Meaning: The sky is very dark, it will probably rain.

In fact, でしょう (deshou) is always used in the weather forecast in Japan. When you are listening to the Japanese news next time, take note of whether the Japanese weathercaster has used this Japanese expression.

More Examples

  1. あのレストランの前にはいつも大勢人がいますから、有名でしょう
    ano resutoran no mae niwa itsumo oozei hito ga imasu kara, yuumei da deshou

    Meaning: There are always many people crowded in front of that restaurant. (Therefore) it might be famous.

  2. マイクさんは十年日本に住んでいましたから、たぶん奥さんは日本人でしょう
    maiku san wa juunen nihon ni sunde imashita kara, tabun okusan wa nihonjin da deshou

    Meaning: Mike had lived in Japan for ten years. (Therefore) his wife might probably be a Japanese.

Some Points to Note

1. The adverb たぶん (tabun), which means "probably", is used quite often with でしょう (deshou), just like in example 2 above.

2. Sometimes だろう (darou) is used instead of でしょう (deshou), especially for man. And だろう (darou) is also the plain-form of でしょう (deshou).

3. When you are reading the above examples, the intonation for でしょう (deshou) is going down. However, if the intonation is going up, it becomes a question to someone and you are seeking his or her agreement. For example...

  • あの人は田中さんでしょう。 ↘(intonation going down)
    ano hito wa tanaka san deshou

    Meaning: I guess that person is Ms Tanaka.

  • あの人は田中さんでしょう。 ↗(intonation going up)
    ano hito wa tanaka san deshou

    Meaning: I guess that person is Ms Tanaka. Is my guess correct?
    (You are guessing that person is Ms Tanaka. But you want to confirm that your guess is correct)

かもしれません kamoshiremasen

かもしれません (kamoshiremasen) is also used to express the speaker's inference or guess about what may possibly happen, though he or she cannot be absolutely certain.

When the speaker says かもしれません (kamoshiremasen), he or she is also aware that the opposite could be true. The degree of certainty is much lower than that of でしょう (deshou) in this case.

Both Japanese expressions share the same sentence patterns. So following that of でしょう (deshou), the sentence patterns of かもしれません (kamoshiremasen) are...

Verb plain-form かもしれません
い-adjective plain-form かもしれません
な-adjective plain-form (~) かもしれません
Noun plain-form (~) かもしれません

Note: For な-adjective & noun, remove the ending だ before かもしれません


  1. 約束の時間に間に合わないかもしれません
    yakusoku no jikan ni maniawanai kamoshiremasen

    Meaning: We might not be in time for the appointment.

  2. 東京は今日寒いかもしれません
    toukyou wa kyou samui kamoshiremasen

    Meaning: It might be cold in Tokyo today.

  3. 山田さんは田中さんが好きかも知れません
    yamada san wa tanaka san ga suki da kamoshiremasen

    Meaning: There is a possibility that Mr Yamada likes Ms Tanaka.

  4. 鈴木さんの部屋は電気がついていません。もう部屋にいないかもしれません
    suzuki san no heya wa denki ga tsuite imasen. mou heya ni inai kamoshiremasen

    Meaning: The light in Mr Suzuki's room is off. He might have left his room already.

  5. もしかしたら3月に卒業できないかもしれません
    moshikashitara san gatsu ni sotsugyou dekinai kamoshiremasen

    Meaning: There is a possibility that I might be unable to graduate in March.

  6. 大きい地震があるかもしれませんから、旅行の前に保険に入ろうと思っています。
    ookii jishin ga aru kamoshiremasen kara, ryokou no mae ni hoken ni hairou to omotte imasu

    Meaning: There is a possibility of a big earthquake, therefore I am thinking of getting the insurance before my trip.

Some Points to Note

1. In example 6, if I were to say 大きい地震があるでしょうから (ookii jishin ga aru deshou kara), it will sound very weird. It's like I am predicting and are 90% sure that there will be a big earthquake happening and therefore I have to get the insurance.

Although we can't really predict whether an earthquake is going to happen, there is still a possibility that it may happen. However the possibility is very much lower (may be 1% or lower). In this case, かもしれません (kamoshiremasen) is more appropriate.

2. The adverb もしかしたら (moshikashitara), which means "perhaps", is used quite often with かもしれません (kamoshiremasen), just like in example 5 above.

3. かもしれない (kamoshirenai) is the plain-form of かもしれません (kamoshiremasen).

Differences Between The Two Japanese Expressions

1. Degree of Certainty

Although both Japanese expressions でしょう and かもしれません are guesses, the degrees of certainty are different. For でしょう, the speaker is more certain about the guess (80% to 90%). Whereas for かもしれません, the certainty is much lower. Maybe 50%, 20%, 10% or even 1%.

As such, the weathercaster in Japanese news will only use でしょう when forecasting weather. If the weathercaster uses かもしれません, no one will believe the forecast.

2. Prediction of Speaker's Volitional Action

でしょう cannot be used when predicting the speaker's volitional action. かもしれません, on the other hand can be used when referring to the speaker's own action or action of other people. For example...

  • 私は来年結婚するでしょう。 X
    watashi wa rainen kekkon suru deshou X
    私は来年結婚するかもしれません。 O
    watashi wa rainen kekkon suru kamoshiremasen O

    Meaning: I guess I will marry next year.

3. Prediction of Future Event

でしょう is often used for prediction of future event.


In summary, depending on the situation that you are in, learn to use these two Japanese expressions でしょう and かもしれません correctly.

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