を, in hiragana, or ヲ in katakana, is one of the Japanese kana, each of which represents one mora. Historically, both are phonemically /wo/, reflected in the Nihon-shikiwo, although the contemporary pronunciation is [o]ⓘ, reflected in the Hepburn romanization and Kunrei-shiki romanization[1]o. Thus it is pronounced identically to the kana o. Despite this phonemic merger, the kana wo is sometimes regarded as a distinct phoneme from /o/, represented as /wo/, to account for historical pronunciation and for orthographic purposes.
Modern usage
In the 1946 orthographic reforms, を was largely replaced by お. In Japanese, this kana is used almost exclusively for a particle for both forms; therefore, the katakana form (ヲ) is rare in everyday language, mostly seen in all-katakana text. A "wo" sound is usually represented as うぉ or ウォ instead.
Despite originally representing [wo], the mora is pronounced [o] by almost all modern speakers. Singers may pronounce it with the [w], as a stylistic effect. Apart from some literate speakers who have revived [wo] as a spelling pronunciation[citation needed], though, this [w] sound is extinct in the modern spoken language. Some non-standard dialectal Japanese still pronounce it [wo], notably dialects in the Ehime Prefecture.[citation needed]
In Romaji, the kana is transliterated variably as ⟨o⟩ or ⟨wo⟩, with the former being faithful to standard pronunciation, but the latter avoiding confusion with お and オ, and being in line with the structure of the gojūon. を is transliterated as o in Modified Hepburn and Kunrei and as wo in Traditional Hepburn and Nippon-shiki.
Katakana ヲ can sometimes be combined with a dakuten, ヺ, to represent a /vo/ sound in foreign words; however, most IMEs lack a convenient way to do this as this usage has largely fallen into disuse. The digraph ヴォ is used far more frequently to represent the /vo/ sound.
Hiragana を is still used in several Okinawan orthographies for the mora /o~wo/; in the Ryukyu University system, it is /o/, whereas お is /ʔo/. Katakana ヲ is used in Ainu for /wo/.
Stroke order
Stroke order in writing を
Stroke order in writing ヲ
Stroke order in writing をStroke order in writing ヲ
