Khitai
Located is in eastern Hyboria. Magic is prevalent and they are constantly at war with Kambuja which lies to the south.
"Then there were camels, and yellow-skinned men who wore silk robes and spoke in a weird tongue. (...) He was a magician from far Khitai, returning to his native kingdom after a journey to Stygia. He took me with him to purple-towered Paikang, its minarets rising amid the vine-festooned jungles of bamboo, and there I grew to womanhood under his teaching. Age had steeped him deep in black wisdom, not weakened his powers of evil. Many things he taught me --"
-- Robert E. Howard:
"A Witch Shall Be Born"
Gazetteer of the Hyborian World
Note - Khitai is roughly analogous to an amalgamation of ancient China and ancient to feudal Japan both culturally and geographically.