o
hiragana katakana
transliteration	o
hiragana origin	於
katakana origin	於
Man'yōgana	意 憶 於 應
spelling kana	大阪のオ (Ōsaka no "o")

In Japanese writing, the kana お (hiragana) and オ (katakana) occupy the fifth place, between え and か, in the modern Gojūon (五十音) system of collating kana. In the Iroha, they occupy the 27th, between の and く. In the table at right (ordered by columns, from right to left), お lies in the first column (あ行, "column A") and the fifth row (お段, "row O"). Both represent [o].

お and オ originate, via man'yōgana, from the kanji 於.

Scaled-down versions of the kana (ぉ, ォ) are used to express morae foreign to the Japanese language, such as フォ (fo).

The hiragana お is made with three strokes:

1. A horizontal line from left to right.
2. A stroke consisting of a vertical line, a small diagonal line going upwards and to the left, and an open curve heading right and downwards.
3. A small curved stroke on the right.

The katakana オ is made with three strokes:

1. At the top, a horizontal stroke from left to right.
2. A downward vertical stroke cutting through the first stroke, with a small hook at the end facing left.
3. At the intersection of the first two strokes, a diagonal line going downwards and to the left.

Japanese radiotelephony alphabet	Wabun code
大阪のオ Ōsaka no "O"	▄ ▄▄▄ ▄ ▄ ▄ ⓘ

Japanese Navy Signal Flag	Japanese semaphore	Japanese manual syllabary (fingerspelling)	Braille dots-24 Japanese Braille

• Full Braille representation

お / オ in Japanese Braille
お / オ o	おう / オー ō/ou	+う / +ー chōon*

* When lengthening "-o" morae in Japanese braille, a chōon is always used, as in standard katakana usage instead of adding an お / オ.

• Computer encodings