Ro (hiragana: ろ, katakana: ロ) (romanised as ro) is one of the Japanese kana, each of which represents one mora. The hiragana is written in one stroke, katakana in three. Both represent [ɾo] ^ⓘ and both originate from the Chinese character 呂. The Ainu language uses a small ㇿ to represent a final r sound after an o sound (オㇿ or). The combination of an R-column kana letter with handakuten ゜ – ろ゚ in hiragana and ロ゚ in katakana – was introduced to represent [lo] in the early 20th century.^{[according to whom?]}