such as the Latin alphabet, Cyrillic script, Greek alphabet, Arabic numerals, etc. for use in information processing. They have had numerous revisions. The current standards are: JIS X 0208, the most recent version of the main standard. It has 6,355 kanji. JIS X 0212, a supplementary standard containing a further 5,801 kanji. This standard is rarely used, mainly because the common Shift JIS encoding system could not use it. This standard is effectively obsolete. JIS X 0213, a further revision which extended the JIS X 0208 set with 3,695 additional kanji, of which 2,743 (all but 952) were in JIS X 0212. The standard is in part designed to be compatible with Shift JIS encoding. JIS X 0221:1995, the Japanese version of the ISO 10646/Unicode standard. Gaiji are kanji that are not represented in existing Japanese encoding systems. These include variant forms of common kanji that need to be represented alongside the more conventional glyph in reference works and can include non-kanji symbols as well. can be either user-defined characters, system-specific characters or third-party add-on products. Both are a problem for information interchange, as the code point used to represent an external character will not be consistent from one computer or operating system to another. were nominally prohibited in JIS X 0208-1997 where the available number of code-points was reduced to only 940. JIS X 0213-2000 used the entire range of code-points previously allocated to , making them completely unusable. Most desktop and mobile systems have moved to Unicode negating the need for gaiji for most users. Nevertheless, they persist today in Japan's three major mobile phone information portals, where they are used for emoji (pictorial characters). Unicode allows for optional encoding of in private use areas, while Adobe's SING (Smart INdependent Glyphlets) technology allows the creation of customized gaiji. The Text Encoding Initiative uses a element to encode any non-standard character or glyph, including gaiji. (The g stands for .) Total number of kanji There is no definitive count of kanji characters, just as there is none of Chinese characters generally. The Dai Kan-Wa Jiten, which is considered to be comprehensive in Japan, contains about 50,000 characters. The Zhonghua Zihai, published in 1994 in China, contains about 85,000 characters, but the majority of them are not in common use in any country, and many are obscure variants or archaic forms. A list of 2,136 jōyō kanji (常用漢字) is regarded