Japan doesn't have UBI, but it's welfare system is extremely expansive as Article 25 of the Constitution guarantees a minimum standard of living through livelihood, housing, education, and medical assistance.

Additonally, Japan has spent decades thinking about this eventuality (at least since the 1970s), which is why Japan worked on the "Flying Geese" paradigm where Japanese public-private ventures would end up become major capital stake holders across Asia, the US, and Europe.