In relation to the Japanese language and computers many adaptation issues arise, some unique to Japanese and others common to languages which have a very large number of characters. The number of characters needed in order to write in English is quite small, and thus it is possible to use only one byte (28=256 possible values) to encode each English character. However, the number of characters in Japanese is many more than 256 and thus cannot be encoded using a single byte - Japanese is thus encoded using two or more bytes, in a so-called "double byte" or "multi-byte" encoding. Problems that arise relate to transliteration and romanization, character encoding, and input of Japanese text.
There are several standard methods to encode Japanese characters for use on a computer, including JIS, Shift-JIS, EUC, and Unicode. While mapping the set of kana is a simple matter, kanji has proven more difficult. Despite efforts, none of the encoding schemes have become the de facto standard, and multiple encoding standards were in use by the 2000s. As of 2017, the share of UTF-8 traffic on the Internet has expanded to over 90 % worldwide, and only 1.2% was for using Shift-JIS and EUC. Yet, a few popular websites including 2channel and kakaku.com are still using Shift-JIS.
Until 2000s, most Japanese emails were in ISO-2022-JP ("JIS encoding") and web pages in Shift-JIS and mobile phones in Japan usually used some form of Extended Unix Code. If a program fails to determine the encoding scheme employed, it can cause "misconverted garbled/garbage characters" and thus unreadable text on computers.
The first encoding to become widely used was JIS X 0201, which is a single-byte encoding that only covers standard 7-bit ASCII characters with half-width katakana extensions. This was widely used in systems that were neither powerful enough nor had the storage to handle kanji (including old embedded equipment such as cash registers) because Kana-Kanji conversion required a complicated process, and output in kanji required much memory and high resolution.