How to speak about "one" thing in Japanese?


In short, what I mean is, how can I mention about one certain thing (not one
thing in amount) in Japanese?

For example "one morning" in the following sentence:

> As Gregor Samsa awoke _**one morning**_ from uneasy dreams he found himself
> transformed in his bed into a gigantic insect.

I come across some usages like " **ある** X". For instance:

  * One morning -> **ある** 朝
  * One day -> **ある** 日

Is this **ある** may be what am I looking for?




> > As Gregor Samsa awoke **_one morning_** from uneasy dreams he found
> himself transformed in his bed into a gigantic insect.
>
> One morning -> ある朝
>
> Is this ある may be what am I looking for?

I can confirm it is the one, as a native speaker.

The kanji version is 或る, but more often it appears in ひらがな: ある人が…, ある時,
あるところにおじいさんとおばあさんが, etc.

We also sometimes say とある: とある日曜の午後 (with rather a feel of popular
literature).

某｛ぼう｝ is yet another possibility, in the same manner: ex. 某日｛ぼうじつ｝,
某会社社長{ぼうかいしゃしゃちょう}, 某ファーストフード店｛てん｝, etc.




> > As Gregor Samsa awoke **_one morning_** from uneasy dreams he found
> himself transformed in his bed into a gigantic insect.
>
> One morning -> ある朝
>
> Is this ある may be what am I looking for?

I can confirm it is the one, as a native speaker.

The kanji version is 或る, but more often it appears in ひらがな: ある人が…, ある時,
あるところにおじいさんとおばあさんが, etc.

We also sometimes say とある: とある日曜の午後 (with rather a feel of popular
literature).

某｛ぼう｝ is yet another possibility, in the same manner: ex. 某日｛ぼうじつ｝,
某会社社長{ぼうかいしゃしゃちょう}, 某ファーストフード店｛てん｝, etc.

