What is "sangju"

Sangju is a city in North Gyeongsang Province, South Korea. Although Sangju is rather rural, it is very old and was once a key city. Along with Gyeongju, it gives rise to half of the name of the Gyeongsang provinces. Sangju is nicknamed Sam Baek, or "Three Whites", referring to three prominent agricultural products rice, silkworm cocoons, and dried persimmons from the area.