Please view the guidelines
Justified Alignment for CJK
Most documents for publications are formatted using “justified alignment”, i.e., the formatting tries to avoid an irregular right border of the text. Currently, this works by distributing the remaining space in a line to the blanks inside this line. However, this procedure does not make sense for languages which do not use blanks the way western languages do. We also have to consider the case of mixed scripts inside a text. Here is a proposal for handling “justified alignment” for CJK languages.
for Japanese text
The remaining space is to be equally distributed to “blanks” and Japanese characters. Note: A blank behind a Japanese character would lead to a double size gap.
for Chinese text
Justified alignment for Chinese to use the same method as Japanese.
for Korean text
The remaining space in a line is to be distributed only to blanks.
Please give feedback if my assumptions are wrong or if you know of some other special cases for other languages.