“Despite its official recognition, Japanese commonly choose between Nihon-shiki/Kunrei-shiki and Hepburn for any given situation. However, the Japanese government generally uses Hepburn, especially for passports,[10] road signage,[10] and train signage.” - Wikipedia.
Personally, my students are completely and utterly inconsistent in usage of romaji, even the students scoring 90%+ on every test. Even if it is the “official” system, I don’t think it’s being enforced very hard. My JTEs even told me before they don’t ever grade or check romaji. A large portion of my students have a tendency to shorten “mu” to just “m,” something I’ve never seen before anywhere.
I’ll do a bit more research into that system, as I find it fascinating I’ve never heard of it until now. Wouldn’t be surprised in the slightest if it’s similar to America’s “official” cursive which is morphed uncontrollably from its original form as soon as students who keep using it enter middle school.
Yup. Pretty much any student whose given name ends in “mu” shortens it in romaji. For example, “Ayum” for 歩夢, “Hirom” for 弘. Four syllable names get the final vowel snipped too a lot, especially ち. 花道, for example, ends up “Hanamich.” Thinking about it more closely now, it never happens on two syllable names or names ending in an あ, え, or お sound. Just い and う.
Though considering how much 当て字 there is among the students’ given names, I’m starting to expect these types of shenanigans.
I would totally, 200% not start learning kanji until you’ve got hiragana and katakana down, and I’m always shocked by (and somewhat fearful for) people on here who say they’re doing the opposite.
Re: Romaji:
Many of my students do seem to largely use the Kunreishiki, though they aren’t actually aware of the different styles and seem to mix freely, often going with whatever they’ve gotten used to for typing.
Hepburn is vastly more readable for foreigners though, in terms of representing the pronunciations, so both I and the Japanese English teachers I work with encourage students to use the latter in their English writing (in such cases as romaji is needed: discussing Japanese food, cultural activities, etc.). No foreigner alive is going to read tu as tsu. As such, Kunreishiki isn’t horribly useful for anything but using romaji to communicate with other native speakers of Japanese.
Anyway, yeah. Don’t use romaji to begin learning kanji. You’re handicapping your ability to read vocabulary, and you’re only approximating the sounds. (Is ふ really fu or hu? It’s neither. There are at least three consonant sounds in Japanese we don’t have in English.)
Just looking at Kunreishiki makes my eyes bleed. I prefer direct transliteration when necessary - except for common city names. It’s hard to think of Tokyo as Toukyou.
Wouldn’t be surprised in the slightest if it’s similar to America’s “official” cursive which is morphed uncontrollably from its original form as soon as students who keep using it enter middle school. 
