Below are two Legal Associations related to those with Japanese interests one might consider looking into:
The Japan Law Society has free membership, and they have a group on LinkedIn, and often post quite a bit about CLEs taking place Japan-side, which may be of little interest to a law student, but can at least let you know what’s going on issue-wise amongst attorneys in Japan.
The second group is for those students who have access to furikomi – The Roppongi Bar Association.
See also numerous other LinkedIn groups that are ancillary to the legal profession, namely groups for Bilingual Japanese, Business in Japan, and Jobs in Japan, not to mention JETAA and any chapter affiliations you might have.