A western Japanese city has issued a residential certificate that describes the partner in a same-sex male couple as unregistered husband.

This is unusual in Japan, as same-sex marriage is not legally recognized.

Matsuura Keita and Fujiyama Yutaro moved to Omura City, Nagasaki Prefecture, in March.

In early May, they applied for a residential certificate, in which they described their relationship as Matsuura being the head of the family and Fujiyama as the unregistered husband.

The city authorities accepted their application form on the spot, and issued a certificate describing their relationship as such.

Matsuura said he couldn't believe this happened and that he was pleased.

Omura City introduced a program last year in which local authorities issue partnership certificates for same-sex couples.

Matsuura said the partnership program is not legally binding for now, but his case may possibly lead to such a program having legal power in the future. He added he hopes other localities will follow suit or encourage debate on these programs.