Dividing Lines of Text in Japanese

Glossary

• Leading characters: Characters—such as opening quotation marks, opening parentheses, and currency signs—that shouldn't be separated from succeeding characters.
• Following characters: Characters—such as closing quotation marks, closing parentheses, and punctuation marks—that shouldn't be separated from succeeding characters.
• Overflow characters: Punctuation characters that are allowed to extend beyond the right margin for horizontal text or below the bottom margin for vertical text.

Japanese line breaking is based on the kinsoku rule—you can break lines between any two characters, with several exceptions. The first exception is that a line of text cannot end with any leading characters, which are listed below. (Characters are shown with their hexadecimal code points for Shift-JIS.)

24		A2		816D		8177
28		8165		816F		8179
5B		8167		8171		818F
5C		8169		8173		8190
7B		816B		8175		8192

The second exception is that a line of text cannot begin with any following characters. Following characters are listed below.

21		B0		8168		82A7
25		DE		816A		82C1
29		DF		816C		82E1
2C		8141		816E		82E3
2E		8142		8170		82E5
3F		8143		8172		82EC
5D		8144		8174		8340
7D		8145		8176		8342
A1		8146		8178		8344
A3		8147		817A		8346
A4		8148		818B		8348
A5		8149		818C		8362
A7		814A		818D		8383
A8		814B		818E		8385
A9		8152		8191		8387
AA		8153		8193		838E
AB		8154		81F1		8395
AC		8155		829F		8396
AD		8158		82A1
AE		815B		82A3
AF		8166		82A5

The third exception is that certain overflow characters are allowed to extend past the right or bottom margin. Those characters that can are listed below.

2C		8141
2E		8142
A1		8143
A4		8144

You must decide how to implement special cases. For example, you might choose to break lines only between complete words instead of between two individual characters. Also, you might want to follow standard English or European line-breaking rules for any text that the user enters using Latin characters.