In general, typographically speaking, Japanese kana and kanji look much better inside Japanese full-width (or 全角, double-byte) parentheses. Because English characters like 'j', 'y' can extend below the baseline, English (半角, half-width) parentheses tend to be positioned slightly lower than Japanese ones.
In some Japanese fonts (such as MS Mincho), this difference may not be noticeable. But in certain fonts, especially professional ones, combination of English parentheses and Japanese texts can produce awful results.
In the world of Japanese professional typography, where main text is written in Japanese, the following is the general rule:
Use English (half-width, single-byte, 半角) parentheses if they contain only English characters. Generally, it is not necessary to insert a space before opening parentheses or after closing parentheses, if your software is good enough. Spaces between symbols and texts should be adjusted via settings (such as
\xkanjiskip in Japanese LaTeX and 文字組みアキ量設定 in InDesign). And of course these software can handle line breaks properly, with or without such spaces. In the screenshot above, you can see that inserting such spaces makes almost no difference in the final output. (Notice the tiny dots in the third line. This is the default behavior of InDesign.)
Always use Japanese (full-width, double-byte, 全角) parentheses if they contain one or more Japanese character(s). Don't insert any spaces before or after the parentheses.
I emphasize that these rules apply when you're typesetting articles mainly written in Japanese. It is common to insert (English, single-byte) spaces before English
( and after English
) if you're writing an email. Japanese Wikipedia has similar guideline.
And of course, if your article is mainly in English, basically you must follow the English style guidelines. As @Earthliŋ states, always sticking to English (half-width) parenthesis is one of the reasonable choices, especially when your software is not very good at Japanese fonts.
But when the situation permits, you can always choose to use Japanese parentheses and pursue the best-looking results:
To my eyes, the second line (Japanese words surrounded by Japanese parentheses, surrounded by English spaces) looks best, even though two types of parentheses coexist in one sentence. But I don't know how it looks to Westerner's eyes, so I would like to hear opinions of others. And you can notice that this software properly adjusts the actual spaces between the words, so you don't have to worry about the unwanted spaces by using "full-width" parentheses.