𛄟

From 汙.

𛄟 • (wu) 

1. The hiragana syllable 𛄟 (wu). Its equivalent in katakana is 𛄢 (wu).

In modern Japanese, old /β̞u/ evolved into /u/, and is written as う in hiragana and ウ in katakana. The sound /β̞u/ was reintroduced later and is written as うぅ in hiragana and ウゥ in katakana - however most speakers pronounce this as a long /u/ sound, i.e. /uː/.

• 𛄟 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, 𛄟 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 𛄟 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(おも)ふ (omofu) as 思(おも)𛄟 (omowu).