Expressing Uncertainty in Japanese

Uncertain Businesswoman
John Wildgoose

There are several ways to express uncertainty in Japanese. "~ darou" is a plain form of "~ deshou," and means "will probably." The adverb "tabun (perhaps)" is sometimes added.

Kare wa ashita kuru deshou.
彼は明日来るでしょう。
He will probably come tomorrow.
Ashita wa hareru darou.
明日は晴れるだろう。
It will be sunny tomorrow.
Kyou haha wa tabun 
uchi ni iru deshou.

今日母はたぶんうちにいるでしょう。
My mother will probably 
be home today.


"~ darou" or "~deshou" is also used to form a tag question.

In this case you usually can tell the meaning from the context.

Tsukareta deshou.
疲れたでしょう。
You were tired, weren't you?
Kyou wa kyuuryoubi darou.
今日は給料日だろう。
Today is a payday, isn't it?


"~ darou ka" or "~ deshou ka" is used when guessing with doubt. "~ kashira" is used only by females. A similar expression used by both genders is "~ kana," though it is informal. These expressions are close to "I wonder ~" in English.

Emi wa mou igirisu ni 
itta no darou ka.

エミはもうイギリスに行ったのだろうか。
I wonder if Emi has 
already gone to England.
Kore ikura kashira.
これいくらかしら。
I wonder how much this is.
Nobu wa itsu kuru no kana. 
のぶはいつ来るのかな。
I wonder when Nobu will come.


"~ kamoshirenai" is used to express a sense of probability or doubt. It shows even more uncertainty than "~ darou" or "~ deshou". It is used when you don't know all the facts and are often just guessing. It is similar to the English expression "might be." The formal version of "~ kamoshirenai" is "kamoshiremasen".

Ashita wa ame kamoshirenai.
明日は雨かもしれない。
It might rain tomorrow.
Kinyoubi desu kara, 
kondeiru kamoshiremasen.

金曜日ですから、
混んでいるかもしれません。
Since it is Friday, it might be busy.


* Compare these sentences.

Kare wa tabun kin-medaru o 
toru deshou.

彼はたぶん金メダルを取るでしょう。
He will probably get the gold medal.
Kare wa kin-medal o 
totta no kana.

彼は金メダルを取ったのかな。
I wonder if he got the gold medal.
Kare wa kin-medaru o 
toru kamoshirenai.

彼は金メダルを取るかもしれない。
He might get the gold medal.


The last thing to mention is, "~ darou" or "~ deshou" can't be used when referring to one's own actions, though "~ kamoshirenai" can be used in these situations.

Ashita watashi wa Kobe ni 
iku kamoshirenai.

明日私は神戸に行くかもしれない。
I might go to Kobe tomorrow.
Ashita watashi wa Kobe ni 
iku darou.
Wrong
Ashita ane wa Kobe ni iku darou.
明日姉は神戸に行くだろう。
My sister will go to Kobe tomorrow.


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