A Japanese court ruled on Wednesday that not allowing same-sex couples to get married is "unconstitutional", setting a precedent in the only G7 nation not to fully recognise same-sex partnership.

The ruling by a district court, the first in Japan on the legality of same-sex marriages, is a major symbolic victory in a country where the constitution still defines marriage as being based on "the mutual consent of both sexes".

Following the ruling, plaintiffs and supporters unfurled...