Placing a space after the first word of a sentence

Question

I was watching a dorama and I realized that in only one minute there was some sentences in which there was a "western-sized" space in the beginning of the sentences (by the way you can do that by pressing "shift + space" when using the Japanese keyboard). For example:

「一体 誰が招待状を送ったのか」
「何 慌ててんのよ？」
「いいかげん 服着てください」

After several times, I realized there wasn't a clear reason to do that. If the reason were to make it clearer, the second and specially the third sentence wouldn't fit this convention. Is there any reason or rule to do that? I think I saw this pattern in mangas before. I like to understand the literary way of writing.

Answer 1

Basically it's an equivalent of a comma (or sometimes a period). In situations where periods and commas are not usually used (subtitles, manga, headlines, ...), spaces can be used instead. You would see spaces typically after だが, でも, それにしても, etc. Sometimes, spaces may be inserted more frequently than commas to increase readability. This is typically common in games and books for children (example 1, 2).

Answer 2

From Netflix’s Japanese subtitles guide (likely a translation of some Japanese guide):

I.18. Punctuation

• Do not use (。) or (、) punctuation
  ◦ Instead of (、) – use half-width character space
  ◦ Instead of (。) – use full-width character space