, From the bottom of 宇. May be confused with 于.
- The katakana syllable (wu). Its equivalent in hiragana is (wu).
- In modern Japanese, old /β̞u/ evolved into /u/, and is written as う in hiragana and ウ in katakana. Sound /β̞u/ reintroduced later is written as うぅ in hiragana and ウゥ in katakana - however most speakers pronounce this as a long /u/ sound.
- is a retrospective invention. It was not actually used in the ancient Japanese literature (which uses man'yōgana instead) and thus is not included in the historical kana orthography.
- In Meiji era grammar books, was sometimes used to spell ワ行下二段活用 verbs.
- In ancient times, all は行 sounds were pronounced /pV/ (“V” being any of the Japanese vowels). Then, during the Nara period, it shifted to /ɸV/ when it was in the middle or at the end of a word. Between the Heian and Kamakura periods, /ɸV/ changed to /βV/→/β̞V/→/V/. Some older grammar books used to show this in ハ行四段活用 verbs, ハ行上二段活用 verbs, and ハ行下二段活用 verbs (e.g. 思ふ (omofu) as 思 (omowu).
- Unlike the hiragana system, used for Japanese language words that kanji does not cover, the katakana syllabary is used primarily for transcription of foreign language words into Japanese and the writing of loan words (collectively gairaigo), as well as to represent onomatopoeias, technical and scientific terms, and the names of plants, animals, and minerals. It is also occasionally used colloquially in some words for emphasis. Names of Japanese companies, as well as certain Japanese language words, are also sometimes written in katakana rather than the other systems. Formerly, female given names were written in katakana.