I have come across this kind of sentence a lot but cannot figure out why the
Japanese construct their sentences like this.

> こうして、国境の両側で二つの町ができたのである。

As I understand, the subject here is 二つの町 and the verb is できた, のである is for
emphasizing author's opinion. But isn't it weird that the sentence has a
subject and verb already, but with the end in のである、it makes me confused that
now, what is the subject of the sentence?
CC BY-SA 4.0
2022-01-07T05:09:06.690
92870
2022-01-07T07:21:28.453
2022-01-07T06:21:18.020
30454
45326
question
grammar
Sentence ends with のである, without a subject
This is called である体 or だ・である調 (with だ), and is often used in writing.
Essentially, である = だ's 連用形 + ある and functions a copula. I assume you'd be fine
with the sentence coming in either of these two forms?

> こうして、国境の両側で二つの町ができたの **だ** 。

> こうして、国境の両側で二つの町ができたの **です** 。

Per [精選版
日本国語大辞典](https://kotobank.jp/word/%E3%81%A7%E3%81%82%E3%82%8B%E4%BD%93-573277)

> **口語文体** の一つ。文末の指定表現に「である」を用いる文体。敬体の「です・ます体」などに対し、常体と呼ばれ、主として **論説・小説**
> など書きことばに用いられる。である調。

だ・である調 is often used as an alternative to です・ます調 and is often invoked in
academic papers, opinion articles, and novels.

For the choice between だ and である when writing in だ・である調, see this answer:

[If writing in である form, when is it necessary to use
だ？](https://japanese.stackexchange.com/q/18666/30454)
CC BY-SA 4.0
2022-01-07T07:21:28.453
92872
2022-01-07T07:21:28.453
30454
92870
answer