Ruby character
Ruby characters or rubi characters () are small, annotative glosses that are usually placed above or to the right of logographic characters of languages in the East Asian cultural sphere, such as Chinese "hanzi", Japanese "kanji", and Korean "hanja", to show the logographs' pronunciation; these were formerly also used for Vietnamese "hán tự" and "chữ nôm", and may still occasionally be seen in that context when reading archaic texts. Typically called just ruby or rubi, such annotations are most commonly used as pronunciation guides for characters that are likely to be unfamiliar to the reader. Examples. Here is an  example of Japanese ruby characters (called "furigana") for Tokyo (""): Most are written with the "hiragana" syllabary, but "katakana" and "romaji" are also occasionally used. Alternatively, sometimes foreign words (usually English) are printed with furigana implying the meaning, and vice versa. Textbooks usually write on-readings with katakana and kun-readings with hiragana. Here is an example of Zhuyin or Bopomofo ruby characters for Beijing (""), Xiao'erjing, and Pinyin. In Taiwan, the main syllabary used for Chinese ruby characters is "Zhuyin fuhao" (also known as "Bopomofo"); in mainland China "pinyin" is mainly used. Typically, unlike the example shown above, zhuyin is used  with a vertical traditional writing and zhuyin is written on the right side of the characters. In mainland China, horizontal script is used and ruby characters (pinyin) are written above the Chinese characters. Xiao'erjing is a Perso-Arabic alphabet, adopted by Hui Muslims and at times utilized as ruby characters in various manuscripts. This system does have its shortcomings, mainly that it has no way of indicating tones. With the spread of pinyin, the usage of this system has been in decline in the past decades. Most manuscripts that do mark the characters with Xiaoèerjing, do so from right-to -left, which is quite unique, compared to other systems. This is because usually such manuscripts include Arabic texts such as the Quran, and the Chinese writing is the explanation or translation. Books with phonetic guides (especially pinyin) are popular with children and foreigners learning Chinese. Here is an example of the Korean ruby characters for Korea (""): Romaja is normally used in foreign textbooks until Hangul is introduced. Ruby characters can be quite common on signs in certain parts of South Korea. Here is an example of the Vietnamese ruby characters ("Chữ Quốc Ngữ)" for Hanoi (""): Chinese characters and its derivations  of it ("Chữ Hán" and "Chữ Nôm") with the Vietnamese Kinh people have fallen out of use in favour of Latin-based script "Chữ Quốc ngữ" during the French colonial period when it was made a part of compulsory education (1920s onwards). Currently still used by Gin people. Uses. Ruby may be used for different reasons: Also, ruby may be used to show the meaning, rather than pronunciation, of a possibly-unfamiliar (usually foreign) or slang word. This is generally used with spoken dialogue and applies only to Japanese publications. The most common form of ruby is called "furigana" or  yomigana and is found in Japanese instructional books, newspapers, comics and books for children. In Japanese, certain characters, such as the sokuon () (little "tsu", ) that indicates a pause before the consonant it precedes, are normally written at about half the size of normal characters. When written as ruby, such characters are usually the same size as other ruby characters. Advancements in technology now allow certain characters to render accurately. In Chinese, the practice of providing phonetic cues via ruby is rare, but does occur systematically in grade-school level text books or dictionaries. The Chinese have no special name for  this practice, as it is not as widespread as in Japan. In Taiwan, it is known as "zhuyin", from the name of the phonetic system employed for this purpose there. It is virtually always used vertically, because publications are normally in a vertical format, and zhuyin is not as easy to read when presented horizontally. Where zhuyin is not used, other Chinese phonetic systems like pinyin are employed. In academic settings, Vietnamese text written in or may be glossed with ruby for modern readers. Sometimes interlinear glosses are visually similar to ruby, appearing above or below the main text in  smaller type. However, this is a distinct practice used for helping students of a foreign language by giving glosses for the words in a text, as opposed to the pronunciation of lesser-known characters. Ruby annotation can also be used in handwriting. History. In British typography, "ruby" was originally the name for type with a height of 5.5 points, which printers used for interlinear annotations in printed documents. In Japanese, rather than referring to a font size, the word became the name for typeset "furigana". When transliterated back into English, some texts rendered the word as "rubi", (a typical romanisation  of the Japanese word , instead of ("rubī"), the expected transliteration of "ruby"). However, the spelling "ruby" has become more common since the W3C published a recommendation for "ruby markup". In the US, the font size had been called "agate", a term in use since 1831 according to the "Oxford English Dictionary". HTML markup. In 2001, the W3C published the Ruby Annotation specification for supplementing XHTML with ruby markup. Ruby markup is incorporated into the XHTML 1.1 specification and in HTML5. For browsers that don't support Ruby natively, Ruby support is most easily added by using CSS rules that are  available on the web. Ruby markup is structured such that a fallback rendering, consisting of the ruby characters in parentheses immediately after the main text, appears if the browser does not support ruby. The W3C is also working on a specific ruby module for CSS level 2, which additionally allows the grouping of ruby and automatic omission of furigana matching their annotated part. Markup examples. Below are a few examples of ruby markup. The markup is shown first, and the rendered markup is shown next, followed by the unmarked version. Web browsers either render it with the correct size and  positioning as shown in the table-based examples above, or use the fallback rendering with the ruby characters in parentheses: Note that Chinese ruby text would normally be displayed in vertical columns to the right of each character. This approach is not typically supported in browsers at present. This is a table-based example of vertical columns: Complex ruby markup. Complex ruby markup makes it possible to associate more than one ruby text with a base text, or parts of ruby text with parts of base text. Unicode. Unicode and its companion standard, the Universal Character Set, support ruby via  these "interlinear annotation" characters: Few applications implement these characters. Unicode Technical Report #20 clarifies that these characters are not intended to be exposed to users of markup languages and software applications. It suggests that ruby markup be used instead, where appropriate. ANSI. ISO/IEC 6429 (also known as ECMA-48) which defines the ANSI escape codes also provided a mechanism for ruby text for use by text terminals, although few terminals and terminal emulators implement it. The PARALLEL TEXTS (PTX) escape code accepted six parameter values giving the following escape sequences for marking ruby text: