It seems like most of Japan.
Japanese is the second most used language on Bluesky
https://bskycharts.edavis.dev/edavis.dev/bskycharts.edavis.d...
Is the same algorithmic connectivity with Japanese happening on Bluesky as it is on Twitter, or are Bluesky's algorithms just as opaque as Twitter's?
I'm not sure myself, however in atproto you can fetch all the data and do analytics, love it or hate it.