User:Bendono/Notes/Romanization

au

 * Nagauta

ou

 * Marunouchi (丸の内)
 * Tsubouchi Shōyō (坪内逍遥)
 * Ikenoue (池ノ上)
 * Inoue (井上)
 * Toyoura
 * Takinoue
 * Setouchi

o vs. ō

 * Ono (小野) vs Ōno (大野)
 * Osaka (小坂) vs Ōsaka (大阪)
 * Oshima vs Ōshima
 * Hiroshi Ito vs Hiroshi Itō
 * Ono, Hyōgo
 * Ono, Fukushima
 * Ōno, Fukui
 * Ōno, Gifu
 * Ōno, Hiroshima
 * Ōno, Hokkaidō
 * Ōno, Iwate
 * Ōno, Ōita
 * Oe Station (小江駅) vs. Ōe Station (大江駅))

oo

 * Toyooka
 * Nishinoomote
 * Soo

ōo

 * Tōon

ōu

 * Ōu Main Line
 * Hizen-Ōura Station
 * Ōu Mountains
 * Fuyuka Ōura
 * Ōuchi Yoshioki

uu

 * Furuu
 * Katsuura
 * Matsuura

Alternatives
Suffix -h to a vowel to represent a long vowel. Leads to new problems: can no longer distinguish between -oh and -ōh; ex: Yōhei.