Unicode Demystified

Half-width and Full-width Characters

Now that we've taken a look at the characters involved and how they work, we can go back and look a little more closely at some of the interesting issues involved in dealing with East Asian characters.

You'll often hear the terms “half-width” and “full-width” (or their Japanese equivalents, hankaku and zenkaku) used in conjunction with various characters. These terms have their origin in the variable-width character encoding standards used for most East Asian languages. Japanese variable-length encodings such as SHIFT-JIS or EUC-JP included the characters from both the JIS X 0201 and JIS X 0208 standards. These standards overlap, resulting in several characters with two different encodings: a one-byte version ...