Curiously enough, Hepburn romanization fixes some ambiguities in Japanese (Japanese written in kana alone) while introducing others.
The ō in Hepburn could correspond to おう or おお or オー. That's an ambiguity.
Where does Hepburn disambiguate?
In Japanese, an E column kana followed by I sometimes makes a long E, like in 先生 (sen + sei -> sensē). The "SEI" is one unit. But in other situations it does not, like in a compound word ending in the E kana, where the second word starts with I. For instance 酒色 (sake + iro -> sakeiro, not sakēro).
Hepburn distinguishes these; the hiragana spelling does not!
This is one of the issues that makes it very hard to read Japanese that is written with hiragana only, rather than kanji. No word breaks and not knowing whether せい is supposed to be sē or sei.
There are curiosities like karaage which is "kara" (crust) + "age" (fried thing). A lot of the time it is pronounced as karāge, because of the way RA and A come together. Other times you hear a kind of flutter in it which articulates two A's.
I have no idea which romanization to use. Flip a coin?
The ō in Hepburn could correspond to おう or おお or オー. That's an ambiguity.
Where does Hepburn disambiguate?
In Japanese, an E column kana followed by I sometimes makes a long E, like in 先生 (sen + sei -> sensē). The "SEI" is one unit. But in other situations it does not, like in a compound word ending in the E kana, where the second word starts with I. For instance 酒色 (sake + iro -> sakeiro, not sakēro).
Hepburn distinguishes these; the hiragana spelling does not!
This is one of the issues that makes it very hard to read Japanese that is written with hiragana only, rather than kanji. No word breaks and not knowing whether せい is supposed to be sē or sei.
There are curiosities like karaage which is "kara" (crust) + "age" (fried thing). A lot of the time it is pronounced as karāge, because of the way RA and A come together. Other times you hear a kind of flutter in it which articulates two A's.
I have no idea which romanization to use. Flip a coin?