US-ASCII 7 bit Japanese Transliteration?

Years ago, I think it was alt.lang.japanese on usenet where there was an official transliteration scheme that only used 7 bit US-ASCII characters. For example, I think, ū was represented as uu. Can you tell me what scheme is used by people with American typewriters?

Wapuro romaji is what the internet generally uses - essentially, written as you would need to type it when using an IME. With perhaps some tweaks for readability.

Thanks. I found a table here A table of romanizations It might be what I am remembering (from sci.lang.japan).

There was also romanizations used for manga on Usenet, like Kimagure Orange Road

I am asking because I am seeing romanizations and being unsure what they represent. I may use Hepburn in notes.

Hepburn was re-designated as the official standard in Japan at the end of last year in place of Kunrei-shiki, though that mostly just to match common practice, because people and organisations had already been using Hepburn (with some modifications) for decades. So yeah, Kunrei-shiki is pretty much obsolete these days.