Ts’wan-chau, China (Google Maps ⧉, OpenStreetMap ⧉)

"To start for foreign countries one must embark at Ts’wan-chau, and then go to the sea of Ts’i-chau (Paracels)."

"when one embarks at Ts’wan-chau and goes southward, he first comes to Champa and afterwards to this country."