Three sources for identifying Japanese release dates...
Click on any of the links below. Each opens a Google search page. Once there, replace DLZ-0185 with the catalog reference of the release you are seeking (in the Google search box). Be sure to include the quotes. Then click on the magnifying glass icon to perform your Google search.
"DLZ-0185" site:http://artist.cdjournal.com"DLZ-0185" site:http://www.suruga-ya.jp"DLZ-0185" site:http://tower.jpWhen Google finds a match, sometimes the release date is included in the excerpted text. If not, click on the link to view the complete page and locate the release date.
You might want to first practice with test case DLZ-0185, which has a release date of 1995-09-08. Once you know where the resulting release date (i.e. 1995-09-08) appears on the page, you'll know where to look going forward even though you don't read Japanese.
In my experience, CDJournal and Suruga provide results about 80% of the time, and Tower provides results about 60% of the time. I like to try all three and cross check the results before updating the LDDb.