Multibyte String
PHP Manual

Basics of Japanese multi-byte encodings

Japanese characters can only be represented by multibyte encodings, and multiple encoding standards are used depending on platform and text purpose. To make matters worse, these encoding standards differ slightly from one another. In order to create a web application which would be usable in a Japanese environment, a developer has to keep these complexities in mind to ensure that the proper character encodings are used.


Multibyte String
PHP Manual