If you’ve spent any time learning Japanese or just getting around Japan, you’ve probably come across romaji — the Roman alphabet version of Japanese. It shows up on signs, maps, train stations and in most textbooks for foreign learners. But not all romaji is the same. Depending on where you look, you might see…
IIRC, it’s a holdover of a failed Meiji-era proposal to “modernise” Japanese by replacing its writing system with the Latin alphabet. (The one advantage it has over Hepburn is that it is unambiguous, and any Japanese text represented in it can be transliterated back into kana without guesswork.)