Use は or が with ある when the phrase doesn't explicit the place


I'm studying japanese from not that long and a doubt came to my mind studying
ある and いる verbs, so sorry in advance if the question isn't clear.

If we take those two phrases as example:

A. つくえ **は** へやにあります

B. へやにつくえ **が** あります

For what I've understood, in the phrase A, I want to underline the location of
the desk, in this case the room. In the phrase B, instead, I want to underline
that in the room there's a desk, so I give more importance to the object, not
to the location.

If I would want to translate the phrase "there's a desk" without pointing out
the location, I can choose between:

C. つくえ **が** あります

D. つくえ **は** あります

indifferently or, if my previous argument is correct, I have to choose C?




The basic difference is already covered in this question: [What's the
difference between wa (は) and ga
(が)?](https://japanese.stackexchange.com/q/22/5010)

The following is a brief summary. As you can see in the above link, each
sentence has two different meanings.

>   * C. つくえがあります。  
>  ① There is a desk.  
>  ② (Among the aforementioned options,) The desk is what exists. [exhaustive-
> listing]
>   * D. つくえはあります。  
>  ① The desk (we are talking about) exists. [thematic]  
>  ② (By contrast / However,) There is a _desk_. [contrastive]
>

Regarding Sentence C:

  * ① You are bringing a desk into the current conversation. In English, you mention something firstly using 'a' (e.g., "a boy") and then talk about it using 'the' (e.g., "the boy"). In sentence C, が in つくえがあります is similar in purpose to the article 'a' in English.
  * ② is a bit tricky, but this is possible when someone asks you "What do you have at home, a desk or a [_kotatsu_](https://en.wikipedia.org/wiki/Kotatsu)?".

Regarding Sentence D:

  * ① When you have been already talking about some desk, and someone asks you "Does the desk exist?" or "Do you really have the desk?" then you would answer, "はい、つくえはあります。"
  * ② If you stress は when you read this out loud, it would be "contrastive." For example, when someone asks "Do you have a _kotatsu_ at home?", you could answer, "いいえ、こたつはありません。つくえはあります。". In English, you would directly stress the "desk" in this situation.

So when you simply want to say "(Look!) There is a desk.", you **have to use
が**. If you said "つくえはあります" in an inappropriate situation, it would sound very
awkward to native speakers.




The basic difference is already covered in this question: [What's the
difference between wa (は) and ga
(が)?](https://japanese.stackexchange.com/q/22/5010)

The following is a brief summary. As you can see in the above link, each
sentence has two different meanings.

>   * C. つくえがあります。  
>  ① There is a desk.  
>  ② (Among the aforementioned options,) The desk is what exists. [exhaustive-
> listing]
>   * D. つくえはあります。  
>  ① The desk (we are talking about) exists. [thematic]  
>  ② (By contrast / However,) There is a _desk_. [contrastive]
>

Regarding Sentence C:

  * ① You are bringing a desk into the current conversation. In English, you mention something firstly using 'a' (e.g., "a boy") and then talk about it using 'the' (e.g., "the boy"). In sentence C, が in つくえがあります is similar in purpose to the article 'a' in English.
  * ② is a bit tricky, but this is possible when someone asks you "What do you have at home, a desk or a [_kotatsu_](https://en.wikipedia.org/wiki/Kotatsu)?".

Regarding Sentence D:

  * ① When you have been already talking about some desk, and someone asks you "Does the desk exist?" or "Do you really have the desk?" then you would answer, "はい、つくえはあります。"
  * ② If you stress は when you read this out loud, it would be "contrastive." For example, when someone asks "Do you have a _kotatsu_ at home?", you could answer, "いいえ、こたつはありません。つくえはあります。". In English, you would directly stress the "desk" in this situation.

So when you simply want to say "(Look!) There is a desk.", you **have to use
が**. If you said "つくえはあります" in an inappropriate situation, it would sound very
awkward to native speakers.

