Same-sex marriage
Reader W. offers some very interesting information on the topic of same-sex marriage in Japan.
Same-sex marriage, she writes, is not recognized in Japan, but many gay couples get around these issues by "adopting" each other. Under Japanese law, anyone can be adopted by anyone, as long as they are one day older and not already in son/daughter relationship with them.
They are listed as an adopted son or daughter of the older person's "koseki tohon," and are legally recognized as family. They in fact automatically take the last name of the person they are adopted by.