computer science

Japanese language and computers

Japanese language and computers is a computer science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Japanese language and computers rather than just read about it. In short: In relation to the Japanese language and computers, many adaptation issues arise, some unique to Japanese and others common to languages that 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.

Key takeaways

Japanese language and computers belongs to computer science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Japanese language and computers to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Japanese language and computers from memory before moving on to harder problems.

Reference excerpt

In relation to the Japanese language and computers, many adaptation issues arise, some unique to Japanese and others common to languages that 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.

Character encodings 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 had expanded to over 90% worldwide, with only 1.2% still using Shift-JIS and EUC. Yet, a few popular websites, including 2channel and kakaku.com, are still using Shift-JIS. Until the 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 mojibake (文字化け, "misconverted garbled/garbage characters"; literally "transformed characters") and thus unreadable text on computers.

The first encoding to become widely used was JIS X 0201, a single-byte encoding that 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. This means that only katakana, not kanji, was supported using this technique. Some embedded displays still have this limitation. The development of kanji encodings was the beginning of the split. Shift JIS supports kanji and was developed to be completely backward compatible with JIS X 0201, and thus is widely embedded in electronic equipment. However, Shift JIS has the unfortunate property that it often breaks any parser (software that reads the coded text) that is not specifically designed to handle it. For example, some Shift-JIS characters include a backslash (0x5C "\") in the second byte, which is used as an escape character in many programming languages.

A parser lacking support for Shift JIS will recognize 0x5C 0x82 as an invalid escape sequence and remove it. Therefore, the phrase causes mojibake.

This can happen, for example, in the C programming language when having Shift-JIS in text strings. It does not happen in HTML since ASCII 0x00–0x3F (which includes ", %, &, and some other used escape characters and string separators) do not appear as the second byte in Shift-JIS, and backslash is not an escape character there. However, it can happen for JavaScript, which can be embedded in HTML pages.

EUC, on the other hand, is handled much better by parsers that have been written for 7-bit ASCII (and thus EUC encodings are used on UNIX, where much of the file-handling code was historically only written for English encodings). But EUC is not backwards compatible with JIS X 0201, the first main Japanese encoding. Further complications arise because the original Internet e-mail standards only support 7-bit transfer protocols. Thus, RFC 1468 ("ISO-2022-JP", often simply referred to as JIS encoding) was developed for sending and receiving emails. In character set standards such as JIS, not all required characters are included, so gaiji (外字 "external characters") are sometimes used to supplement the character set. Gaiji may come in the form of external font packs, where normal characters have been replaced with new characters, or the new characters have been added to unused character positions. However, gaiji are not practical in Internet environments since the font set must be transferred with the text to use the gaiji. As a result, such characters are written with similar or simpler characters in place, or the text may need to be encoded using a larger character set (such as Unicode) that supports the required character. Unicode was intended to solve all encoding problems for all languages. The UTF-8 encoding used to encode Unicode in web pages does not have the disadvantages that Shift-JIS has. Unicode is supported by international software, eliminating the need for gaiji. There are still controversies, however. For Japanese, the kanji characters have been unified with Chinese; that is, a character considered to be the same in both Japanese and Chinese is given a single number, even if the appearance is actually somewhat different, with the precise appearance left to the use of a locale-appropriate font. This process, called Han unification, has caused controversy. The previous encodings in Japan, the Taiwan Area, Mainland China, and Korea have only handled one language, and Unicode should handle all. The handling of Kanji/Chinese has, however, been designed by a committee composed of representatives from all four countries/areas.

Text input

… excerpt ends here. Continue reading the full article.

Illustrations

Worked examples

Example 1 — a first encounter with Japanese language and computers

Start with the simplest possible case. Write down what Japanese language and computers claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In computer science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Japanese language and computers before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Japanese language and computers ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Japanese language and computers

In research: Japanese language and computers appears in computer science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Japanese language and computers in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Japanese language and computers is common in secondary-school and first-year university syllabi. It links to neighbouring topics Encodings of Japanese, Japanese-language computing, Japanese writing system, so understanding it makes those chapters shorter.
In everyday life: Look for Japanese language and computers outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Japanese language and computers in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Japanese language and computers means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Japanese language and computers out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Japanese language and computers in simple terms?

Why does Japanese language and computers matter?

Because it connects several computer science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Japanese language and computers?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Japanese language and computers.