I still don't understand why Japan and South Korea aren't going to join the Free World. 
Korea is full of homophobic evangelical Christians (thank the US military for that!). Japan is way too knee-jerk conservative on literally everything (can't even get their house in order enough to make women able to inherit the throne) to think about something like this.
Unclear to me how high it is on the list of priorities in Taiwan (and I know Tsai has become rather unpopular so doesn't have the political capital to spend on it), but I would still say Taiwan is by far the best bet for same-sex marriage in east Asia sometime soon, and the courts have in theory guaranteed that it will happen in 2019 if not sooner. Chinese culture generally is much more liberal/permissive than the very traditional Korea and especially Japan, and China overall would likely be a lively liberal society today if things had gone somewhat differently at a variety of different potential junctures in the first half of the 20th century.
