The courts recognized their common-law partnership even though same-sex marriage not being legal in the country.
Although same-sex marriage isn't legal in Japan, the Mooka branch of the Utsunomiya District Court in Tochigi Prefecture awarded a woman damages who broke up with her common-law partner over infidelity.
The defendant must pay the plaintiff 1.1 million yen ($10,170) of the 6.3 million yen she was asking for according to Kyodo News.
Court documents state the couple moved in together back in 2010. Four years later they got a marriage certificate in the United States and had a ceremony in Japan in 2015.
The defendant wanted to raise a child with the plaintiff and found someone who was willing to be the donor through a social networking site.
But according to the case the defendant became romantically involved with the donor in 2017 thus causing resentment in the relationship.
Once the defendant gave birth, the donor underwent gender reassignment surgery.
The plaintiff had bought a home to raise the family and also funded the artificial insemination procedure.
There are no protections for same-sex partnerships in Japan. The plaintiff said her relationship with the defendant should have the same protections as common law marriages, especially since they had a wedding ceremony and had been long-time domestic partners.
The defendant didn't agree according to the report, saying their relationship was not protected under Japanese law.