A moratorium is in effect on adding information from Fire and Blood until December 20th.
Yin is the great port city of Yi Ti on the Jade Sea. It is connected by a trade route to Asabhad to the northwest. A river from the forests of Yi Ti leads south to Yin.
The dynasties of the grey, indigo, and pearl-white emperors ruled the Golden Empire of Yi Ti from their seats at Yin, and, in the present, the azure emperors have done the same.
Yin has not yet been mentioned in A Song of Ice and Fire, only appearing in The Lands of Ice and Fire and A World of Ice and Fire.