- Contents -
  Q What is a personal computer?
  Q How do personal computers output Kanji?
  Q What is a font?
  Q What is a character code?
  Q How are Kanji input?
  Q Is it impossible to use characters not in the character set?
  Q Do I only need a user-defined character editor to use user-defined characters?
  Q How do I input user-defined characters with IME?
  Q Is it possible to use characters from mainframes?
  Q What is the JIS code?
  Q What is the Shift JIS code?
  Q What is Unicode?
  Q How long will it take for Unicode to become available?
  Q What is XKP?
  Q Can user-defined characters be transferred using XKP?
  Q Is it possible to use more user-defined characters than the number of character codes available?
  Q Can XKP user-defined characters be printed?

Japanese Processing Guidebook


Q What is a character code?

A Numbers that represent characters.

When handling characters on a PC, it is normal to replace them with numbers called character codes.
Character codes are no more than numbers, so if the same number is given to different characters, it becomes impossible to judge which character it is expressing. For this reason, it is necessary to set down strict rules on which number should be given to which character.
Normally, official organizations such as JIS collect a certain range of characters into a group, called a character set, to which non-duplicate numbers are then given.
However, when creating a character set, one character code is given to a group of characters that, within limits, differ only slightly.
This takes real-world usage into account. Some Kanji, although they are the same character, have two or more ways of being written. For example, there are some people who consider slight variations in shape, the number of strokes, the existence of a small curve at the end of a stroke, and so on, to be important, and refuse to recognize their name without such features.
However, JIS considers them to be the same character and gives these characters only one character code. Recognizing people's claims without limit would result in the number of characters increasing explosively, increasing the cost of systems. This would reduce the merits of PCs as products that can be used economically.
Thus, when creating a character set, rules are laid down and characters that have a certain level of difference are given separate character codes based on those rules.
Integrating slightly different characters into one in this way is called "connotation".