There isn’t a Japanese classical guideline, so the handling isn’t really standardized for classical. Here’s a few things I usually do when entering Japanese classical releases:
- Using the OBI/spine for the title, especially if it’s in Japanese but the cover is in English.
- The use of colons to separate work and movement are not common in Japanese (space is used instead, since spaces are a more natural separator),
- Using a fullwidth ／ instead of / and no spaces to denote multiple works. Again, punctuation matching the country.
I do use regular commas and semicolons for the artist credit, it’s meant to be a list type of entries. There’s a recent discussion on it: Japanese classical commas
Using the exclusively the front cover for Japanese releases in particular is not a good idea, the OBI is part of the packaging and clearly visible as part of the front cover on a physical release. It’s almost always in Japanese. Therefore, it makes sense for Japanese releases to put the English title on the front cover in addition to the canonical title on the front cover, since the OBI is almost always in Japanese, not vice versa. This is how the release packaging actually looks.
Previous discussion, although not related to classical:
edit #80089945 - rejected series of edits trying to change based on artwork
edit #75112784 - Japanese artist credits
edit #34139763 - front cover as source for title on Japanese releases