is the happenstance of incorrect, unreadable characters shown when computer software fails to render text correctly according to its associated character encoding.

Causes

Mojibake is often caused when a character encoding is not correctly tagged in a document, or when a document is moved to a system with a different default encoding. Such incorrect display occurs when writing systems or character encodings are mistagged or "foreign" to the user's computer system: if a computer does not have the software required to process a foreign language's characters, it will attempt to process them in its default language encoding, usually resulting in gibberish. Messages transferred between different encodings of the same language can also have mojibake problems. Japanese language users, with several different encodings historically employed, would encounter this problem relatively often. For example, the intended word "文字化け", encoded in UTF-8, is incorrectly displayed as "文字化け" in software that is configured to expect text in the Windows-1252 or ISO-8859-1 encodings, usually labeled Western.

A web browser may not be able to distinguish a page coded in EUC-JP and another in Shift-JIS if the coding scheme is not assigned explicitly using the HTTP headers sent along with the documents, or using the HTML document's meta tags that are used to substitute for missing HTTP headers if the server cannot be configured to send the proper HTTP headers. Heuristics can be applied to guess at the character set, but these are not always successful.

In the mid 1990s, as this problem became common, several websites featured mojibake not as a problem to be tackled but simply for amusement. Words and even sentences were "deciphered" with meanings made up to deliver funny messages.

Mojibake can also occur between what appears to be the same encodings. For example, some software by Microsoft and Eudora for Windows purportedly encoded their output using the ISO-8859-1 encoding while, in reality, used Windows-1252 that contains extra printable characters in the C1 range. These characters were not displayed properly in standards-compliant software, this especially affected software running under other operating systems (e.g. Unix).

Resolutions

Applications using UTF-8 as a default encoding may achieve a greater degree of interoperability due to its widespread use and backwards compatibility with US-ASCII.

The difficulty of resolving an instance of mojibake varies depending on the application within which it occurs and the causes of it. Two of the most common applications in which mojibake may occur are web browsers and word processors. Modern browsers and word processors often support a wide array of character encodings. Browsers often allow a user to change their rendering engine's encoding setting on the fly, while word processors allow the user to select the appropriate encoding when opening a file. It may take some trial and error for users to find the correct encoding.

The problem gets more complicated when it occurs in an application that normally does not support a wide range of character encoding, such as in a non-Unicode computer game. In this case, the user must change the operating system's encoding settings to match that of the game. However, changing the system-wide encoding settings can also cause Mojibake in pre-existing applications. In Windows XP or later, a user also has the option to use Microsoft AppLocale, an application that allows the changing of per-application locale settings. Even so, changing the operating system encoding settings is not possible on earlier operating systems such as Windows 98; to resolve this issue on earlier operating systems, a user would have to use third party font rendering applications.

Problems in specific languages

Mojibake in English texts generally occurs in punctuation, such as em dashes (—), en dashes (–), and curly quotes (“, ”), but rarely in character text, since most encodings agree with ASCII on the encoding of the English alphabet. For example, the pound sign "£" will appear as "£" if it was encoded by the sender as UTF-8 but interpreted by the recipient as CP1252 or ISO 8859-1. If iterated, this can lead to "£", "£", etc.

In Japanese, the phenomenon is, as mentioned, called mojibake . It is often encountered by non-Japanese when attempting to run software written for the Japanese market.

Users of Central and Eastern European languages can also be affected. Because most computers were not connected to any network during the mid- to late-1980s, there were different character encodings for every language with diacritical characters.





In Russian slang, mojibake is humorously called krakozyabry ( , meaning "childish scribbles"). During the 1990s, several different encodings for the Cyrillic alphabet (Unix KOI8-R, Windows CP-1251, DOS 866, standard ISO 8859-5, and several others) competed. Poorly configured servers and lack of compatibility made garbled text a common and frustrating experience. Many e-mail servers stripped the eighth bit from the characters, as permitted by earlier standards (which rendered UTF-8 unreadable, as well as the non-KOI8 Russian encodings). For this reason many Cyrillic users resorted to Volapuk encoding. An even more frustrating problem emerged in the early 2000s, when the popular e-mail client Microsoft Outlook started to replace correctly entered Cyrillic characters with question marks when replying to or forwarding messages created in competing encodings.

In Bulgarian, mojibake is often called maymunitsa (маймуница), meaning monkey's alphabet. In Serbian, it is called (đubre), meaning trash. In German, Buchstabensalat (letter salad) and Krähenfüße (crow's feet) are common terms for this phenomenon.

In Poland every company selling early DOS computers created its own encoding, and simply reprogrammed the EPROMs of the video cards (typically CGA, EGA or Hercules) with the needed glyphs for Polish — arbitrarily located without reference to where other computer sellers had placed them. Additionally, users of then-popular home computers (such as the Atari ST) invented their own encodings, incompatible with international standards (ISO 8859-2), vendor standards (IBM CP852, Windows CP1250) and locally agreed-upon PC/MS DOS standards (Mazovia). The situation began to improve when, after pressure from academic and user groups, ISO 8859-2 succeeded as the "Internet standard" with limited support of the dominant vendors' software (today largely replaced by Unicode). With the numerous problems caused by the variety of encodings, even today some users tend to refer to Polish diacritical characters as krzaczki ("bushes").

Commodore brand 8-bit computers used PETSCII encoding, particularly notable for inverting the upper and lower case compared to standard ASCII. PETSCII printers worked fine on other computers of the era, but flipped the case of all letters.

Among the Nordic languages, mojibake is not uncommon, but is more of an annoyance than a problem. Finnish and Swedish use the letters of the English alphabet and three more characters: å, ä and ö, and typically these three are the only ones that become corrupted. The situation is similar for Norwegian and Danish, except the three relevant letters are æ, ø and å. In Swedish, Norwegian and Danish, vowels are rarely repeated, and it is usually obvious when one character gets corrupted, such as the second letter in "kärlek" (kärlek, "love"). This way, even though the reader has to guess among å, ä and ö, almost all texts remain perfectly readable. However, Finnish does have repeating vowels in words like "Hääyö" (hääyö), which can sometimes render text very hard to read. Icelandic is worse off, with possibly confounding characters being ten: á, ð, é, í, ó, ú, ý, þ, æ and ö.

Another type of mojibake occurs when text is erroneously parsed in a multi-byte encoding, such as one of the east Asian encodings. With this kind of mojibake more than one (typically two) characters are corrupted at once, e.g. "k舐lek" (kärlek) in Swedish, where "är" is parsed as "舐". Compared to the above mojibake, this is harder to read, since letters unrelated to the problematic å, ä or ö are missing, and is especially problematic for short words starting with å, ä or ö such as "än" (which becomes "舅"). Since two letters are combined, the mojibake also seems more random (over 50 variants compared to the normal three, not counting the rarer capitals). In some rare cases, an entire text string which happens to include a pattern of particular word lengths, such as the sentence "Bush hid the facts", may be misinterpreted.

In most of former Yugoslavia, an addition to the basic Latin alphabet are the letters š, đ, č, ć, ž, and their capital counterparts Š, Đ, Č, Ć, Ž. All of these letters are defined in Latin2 and Windows-1250, while only some (š, Š, ž, Ž, Đ) exist in the usual OS-default Western. Although even those that exist in extended Western ASCII (Windows-1252) are not immune to errors, the ones that don't are much more prone to errors. Thus, even nowadays, "šđčćž ŠĐČĆŽ" is all too often interpreted as "šðèæž ŠÐÈÆŽ", making users wonder where ð, è, æ, È, Æ are used. When confined to basic ASCII (most usernames, for example), common replacements are: š→s, đ→dj, č→c, ć→c, ž→z (capital forms analogously, with Đ→Dj or Đ→DJ depending on word case). All of these replacements introduce ambiguities, so reconstructing the original from such a form is usually done manually if required.

Hungarian is another affected language, which uses the 26 basic English characters, plus the accented forms á, é, í, ó, ú, ö, ü (all present in the Latin-1 character set), plus the 2 characters ő and ű, which are not in Latin-1. These 2 characters can be correctly encoded in Latin-2, Windows-1250 and Unicode. Before Unicode became common in e-mail clients, e-mails containing Hungarian text often had the letters ő and ű corrupted, sometimes to the point of unrecognizability. It is common to respond to an e-mail rendered unreadable by character mangling (referred to as "betűszemét", meaning "garbage lettering") with the phrase "Árvíztűrő tükörfúrógép", a nonsense phrase (literally "Flood-resistant mirror-drilling machine") containing all accented characters used in Hungarian.

Esperanto was once commonly encoded in Latin-3 to display the accented characters: ĉ, ĝ, ĥ, ĵ, ŝ, and ŭ. In some browsers these characters would be incorrectly displayed as Latin-1 characters with the same encoding: æ, ø, ¶, ¼, þ, and ý.

Another affected language is Arabic (see below).

A similar effect can occur in Indic text, even if the character set used is properly recognized by the application. This is because, in many Indic scripts, the rules by which individual letter symbols combine to create symbols for syllables may not be properly understood by a computer missing the appropriate software, even if the glyphs for the individual letter forms are available.

A particularly notable example of this is the Wikipedia logo, which attempts to show the character analogous to "w" or "wi" (the first letter or syllable of "Wikipedia") on each of many puzzle pieces. Instead, the puzzle piece meant to bear the Sanskrit character for "wi" actually shows a somewhat nonsensical scribble with a dangling line at the end, easily recognizable as mojibake generated by a computer not configured to display Indic text. That this occurs in the venerable front-page logo and has never been corrected over many years has been seen as humorously emblematic of Wikipedia's alleged accuracy and reliability problems.

Example

Output encoding	Setting in browser	Result
Arabic example:		منتدى عرب شير مشاهدة الملف الشخصي
Windows-1251	ISO 8859-1	منتدى عرب شير - مشاهدة الملف الشخصي
	KOI8-R	ы┘ы├ь╙ь╞ы┴ ь╧ь╠ь╗ ь╢ы┼ь╠ - ы┘ь╢ь╖ы┤ь╞ь╘ ь╖ы└ы┘ы└ы│ ь╖ы└ь╢ь╝ь╣ы┼
	ISO 8859-5	й й†иЊиЏй‰ иЙиБиЈ иДйŠиБ - й иДиЇй‡иЏиЉ иЇй„й й„й иЇй„иДиЎиЕйŠ
	CP 866	Е┘Ж╪к╪п┘Й ╪╣╪▒╪и ╪┤┘К╪▒ - ┘Е╪┤╪з┘З╪п╪й ╪з┘Д┘Е┘Д┘Б ╪з┘Д╪┤╪о╪╡┘К
Windows-1256	ISO 8859-6	ظ…ظ†طھط¯ظ‰ ط¹ط±ط¨ ط´ظٹط± - ظ…ط´ط§ظ‡ط¯ط© ط§ظ„ظ…ظ„ظپ ط§ظ„ط´ط®طµظٹ
	CP 852	┘ů┘ćě¬ě»┘ë ě╣ě▒ěĘ ě┤┘Őě▒ - ┘ůě┤ěž┘çě»ěę ěž┘ä┘ů┘ä┘ü ěž┘äě┤ě«ěÁ┘Ő
	ISO 8859-2	٠نتدى عرب شير - ٠شاهدة ال٠لف الشخصي
	ASMO 708	عàع╢ظ╔ظ»عë ظ╥ظ▒ظ╟ ظ═عèظ▒ - عàظ═ظ╞عçظ»ظ╚ ظ╞ع╡عàع╡ع┤ ظ╞ع╡ظ═ظ«ظ╬عè

References

External links

• Reprinted article from the Japan Times
• Coldfusion Developers Guide article
• Online decoder of Hebrew text - Online decoder converts input into readable Hebrew text
• Translators guide
• Recovery tool – Recovery of Japanese text
• Recovery tool – Recovery of Japanese text
• Chinese E-mail Fixer – Recovery of Chinese text
• Decodr.ru - Fast Cyrillic decoder of e-mail and charsets
• Universal Cyrillic decoder - Recovery of Cyrillic text
• Multilingual online text decoder - Online decoder converts scrambled input into readable text. Supported languages are Russian, Bulgarian, Greek, Hebrew and Thai.
• Noto pri ĉapeloj: Resuma tabelo - Covers most cases of Esperanto mojibake.