The existing systems of romanizing Japanese are unsatisfactory: Hepburn doesn't map directly to kana, Kunrei-shiki and Nihon-shiki's pronunciation is not obvious to non-natives (the primary users of rōmaji), waapuro is an anything-goes mess, and JSL is just odd. So, I've come up with my own solution, that I believe incorporates the best aspects of all of them. The advantages:
Of course, there are disadvantages:
- Pronunciation is unambiguous. There is only one case where the pronunciation the spelling suggests to a naïve speaker isn't really correct, but it's rare and close enough to be minor.
- There is a direct mapping to and from kana.
- Pitch accent—which can be phonologically salient—is marked, like JSL but unlike all other systems (including kana).
- Can be written entirely in the Latin-1 character set.
- A standard way of spelling a trailing small tsu.
- Marking for rendaku
Of course, there are disadvantages:
- That one case where the spelling doesn't precisely suggest the proper pronunciation.
- Since it differentiates between homophonous kana, the spelling can not always be unambiguously determined from pronunciation by a naïve listener; however, the simpler spelling is usually the correct one.
- Unlike NS and KS, it is not strictly "one consonant, one letter". I'm not sure if that's really much of a disadvantage at all, frankly.
- Some verb conjugations seem slightly irregular. It shares this problem with Hepburn, but it seems to be a necessary compromise for good naïve pronunciation. And since kana are usually taught in organized rows and columns, I don't think it's much of a stumbling block.