Japan’s capital plans to introduce same-sex partnerships in April, Tokyo Governor Yuriko Koike said, a significant shift for the country’s biggest population center. “From the point of view of advancing understanding of sexual diversity, as well as reducing the problems faced by those involved, we will lay out basic principles for introducing a same-sex partnership system in the next fiscal year,” Koike told an assembly meeting Tuesday. She did not give details of the proposal that will recognize same-sex relationships without giving them full legal status.