World Map

[Hinoto-no-Ryuji]

Bukyo, I believe (going off this image here; my Eorzean script game is pretty weak).

Given its landmark status and its general location, I'm willing to confidently say that it's the capital of Koshu, and probably all of Hingashi - the Hydaelyn equivalent of Edo (medieval Tokyo). The -kyo ending, which can mean "capital" in Japanese, further implies this.

Beyond that, I don't *think* we know anything else, although I'm not sure if it comes up in any of the ambient NPC dialog, flavor text, etc. of Stormblood.