Sistim romanisasi Basa Jepang mimiti dumasar kana [[Orthography of Portuguese|ortografi Basa Portugis]]. Mimiti dimekarkeun kira-kira taun 1548 ku urang Jepang Katolik nyaeta Yajiro. Penerbit [[Society of Jesus|Yesus]] make sistim dina runtuyan buku [[Roman Catholicism|Katolik]] keur kaperluan misionaris dina hotbah jeung pangajaran Kristen sangkan teu kudu diajar maca tulisan Basa Jepang. Pamakean buku ieu loba gunana keur diajar cara ngucapkeun Basa Jepang Modern sarta keur kaperluan romanisasi mimiti dina ''[[Nippo jisho]]'', kamus Basa Jepang-Portugis nu ditulis dina tau 1603. Sacara ilahat, sistim [[Portuguese|Basa Portugis]] mimiti ampir sarua jeung Nihon-shiki dina ngagunakeun ''vowel''. Sababaraha konsonan ditranslasi beda-beda: contona, konsonan /k/ dijieun "c", sarta konsonan /ɸ/ (ayeuna diucapkeun /h/) dijieun "f", mangka ''Nihon no kotoba'' ("Basa Jepang") diejana "Nifon no cotoba". Penerbit Yesus oge ngaluarkeun sababaraha buku sekuler di romanisasi Basa Jepang, nyaeta buku nu mimiti terbit dina Basa Jepang Klasik ''[[The Tale of the Heike]]'', diromanisasi jadi ''Feiqe no monogatari'', sarta koleksi ''[[Aesop's Fables]]'' (diromanisasi jadi ''Esopo no fabvlas''). Nu kadua terus dicetak sarta dibaca sanggeus era Kristenisasi (Chibbett, 1977).
Following the expulsion of Christians from Japan in the late 1590s and early 1600s, ''rōmaji'' fell out of use, and were only used sporadically in foreign texts until the mid-1800s, when Japan opened up again. The systems used today all developed in the latter half of the [[19th century]].
The first system to be developed was the Hepburn system, developed for [[James Curtis Hepburn]] 's dictionary of Japanese words and intended for foreigners to use.
In the [[Meiji era]], some Japanese scholars advocated abolishing the Japanese writing system entirely and using ''rōmaji'' in its stead. The ''Nihon shiki'' romanization was an outgrowth of this movement. Several Japanese texts were published entirely in ''rōmaji'' during this period, but it failed to catch on, perhaps because of the large number of [[homophone]] s in Japanese, which are pronounced similarly but written in different characters. Later, in the early [[20th century]], some scholars devised [[syllabary]] systems with characters derived from Latin; these were even less popular, because they were not based on any historical use of the Latin alphabet.