This Ruby library convert known Japanese names in Kanji or Hiragana to Romaji, or ASCII.
$ gem install japanese-name
JapaneseName.given_name_to_hiragana("清") => "きよし"
JapaneseName.given_name_to_ascii("清") => "kiyoshi"
JapaneseName.family_name_to_hiragana("鎌田") => "かまた"
JapaneseName.family_name_to_ascii("鎌田") => "kamata"
So far it works only with name parts (Family name, or given name). There could be a feature to guess what is the family name and what is the given name. But I don't need it for now, so won't do it until somebody request that.
The names are grabbed from: http://web.archive.org/web/20060518234359/http://www.kokemus.kokugo.juen.ac.jp/names/namae/NA-index.html
To update the names, run:
rake update_data
rake update_surname
For duplicated entries, now the solution is to take only the more frequent spelling.
It knows 59044+ (Mar 2016) Japanese family name and/or given names. It throws except for unknown name. Sorry for the exception, I know it's annoying. But is there a better alternative?