Text: “Tokyo ward Shibuya certifies same-sex partnerships”

Extract: The Shibuya ward in Tokyo has become the first place in Japan to recognise same-sex partnerships. It passed an ordinance allowing officials to issue certificates to same-sex couples this summer. The documents are not legally binding but the ward is calling on businesses to recognise the certificates and accord equal treatment. Japan remains a conservative country but is seeing social shifts on issues such as gay rights. The nation’s constitution identifies marriage as a union between “both sexes”. https://www.bbc.com/news/world-asia-32130599

The Japanese constitution is explicit in its definition of marriage. However, the people of Japan are free to interpret it (and change it) as they see fit. How should Japanese people judge good from bad interpretations of the constitution?