Japan's first official same-sex couple terminated their partnership on Christmas Day.

Actress and LGBT (lesbian, gay, bisexual and transgender) activist Koyuki Higashi and entrepreneur Hiroko Masuhara released a statement earlier this week saying they have returned their partnership certificate to Tokyo's Shibuya Ward on Monday, ending their six-and-a-half year relationship.

It was the same ward office that gave the couple the nation's first certificate recognizing same-sex partnerships in November 2015.

"We carefully discussed whether our personal decisions won't dampen the improving environment surrounding LGBT in Japan," the two said in a joint statement posted on their websites, which said they will remain good friends despite the break-up.

Higashi and Masuhara — who heads a consultancy raising LGBT awareness — became the first same-sex couple to hold a wedding ceremony at Tokyo Disney Resort in 2013, although their marriage had no legal standing.

In 2015, Shibuya and Setagaya wards became the first districts in Japan to issue partnership certificates designed to encourage landlords and hospitals to treat gay couples the same as married ones. Since then several other municipalities have followed suit, issuing similar certificates.

Same-sex marriage is not recognized in Japan and same-sex couples have long faced difficulty when seeking apartments. Some even face obstacles when visiting critically ill partners in hospitals on the grounds that they are not related.

In 2014, Higashi, who is a former member of the all-woman Takarazuka Revue troupe, published a book revealing how she had been sexually abused by her father as a child. She and Masuhara have also co-authored books describing their lifestyle.

"We will continue to work together on issues surrounding LGBT, SOGI (Sexual Orientation and Gender Identity) and women and children's rights," they said.