When is ō romanised ou Vs oh?


Top of my head, I think of these 6 anime/manga:

ō's that are 'oh'

  1. [Tamaki Suoh](https://ouran.fandom.com/wiki/Tamaki_Suoh) (須王 環 Suō Tamaki) from OHSHC
  2. [Ōtsuki](https://kaiji.fandom.com/wiki/Ootsuki) (大槻) from Kaiji - ok I can't find on the fandom page, but I swear the subs say Ohtsuki instead of Outsuki
  3. [Kaname Ohgi](https://codegeass.fandom.com/wiki/Kaname_Ohgi) (扇 要, Ōgi Kaname) from Code Geass

Vs

  1. [Shion no Ō](https://en.wikipedia.org/wiki/Shion_no_%C5%8C) (しおんの王, lit. Shion's King) - Does it count if [MAL romanises](https://myanimelist.net/anime/2562/Shion_no_Ou) as ou not oh?
  2. [The Devil Is a Part-Timer!](https://en.wikipedia.org/wiki/The_Devil_Is_a_Part-Timer!) (Japanese: はたらく魔王さま!, Hepburn: Hataraku Maō-sama!, lit. "Working Demon King!" or "Demon Lord at Work!") - Sadao Maou (Satan, 真奥 貞夫, Maō Sadao)
  3. [Maoyū: Maō Yūsha](https://en.wikipedia.org/wiki/Maoyu) (まおゆう魔王勇者, "Demon King and Hero") - I guess similarly it's gonna be Maou Yūsha. (I think Maoyū should even be Maōyū ?)

Guess:

When it's a name, use h? Idk. As for the Maō-sama case, I believe 'Maō' is not
really a name but a title similar to 'Maō' in Maōyū.




In terms of names used in passports today, either **o** or **oh** is fine and
it is a matter of choice (of the person who applies in case of passport).

E.g., [the guide](https://www.boston.us.emb-
japan.go.jp/itpr_ja/passport7.html) from the consulate-general of Japan in
Boston has the following as allowed romanization for passport names.

氏名のフリガナ | ヘボン式ローマ字 | OHによる長音表記  
---|---|---  
オオ | O | OH  
例：オオノ | ONO | OHNO  
コオリ | KORI | KOHRI  
オウ | O | OH  
例：コウノ | KONO | KOHNO  
オウギ | OGI | OHGI  
  
As noted in the guide, originally only _o_ , which is _the_ correct one in
Hepburn romanization, was allowed.

The following contains how おう/おお are transcribed in other romanization.

  * [Wikipedia/ローマ字](https://ja.wikipedia.org/wiki/%E3%83%AD%E3%83%BC%E3%83%9E%E5%AD%97)




In terms of names used in passports today, either **o** or **oh** is fine and
it is a matter of choice (of the person who applies in case of passport).

E.g., [the guide](https://www.boston.us.emb-
japan.go.jp/itpr_ja/passport7.html) from the consulate-general of Japan in
Boston has the following as allowed romanization for passport names.

氏名のフリガナ | ヘボン式ローマ字 | OHによる長音表記  
---|---|---  
オオ | O | OH  
例：オオノ | ONO | OHNO  
コオリ | KORI | KOHRI  
オウ | O | OH  
例：コウノ | KONO | KOHNO  
オウギ | OGI | OHGI  
  
As noted in the guide, originally only _o_ , which is _the_ correct one in
Hepburn romanization, was allowed.

The following contains how おう/おお are transcribed in other romanization.

  * [Wikipedia/ローマ字](https://ja.wikipedia.org/wiki/%E3%83%AD%E3%83%BC%E3%83%9E%E5%AD%97)

