Joseon is a closed country. Joseon has dealing with only Japanese of Tushima. The base of trading is in Busan, a city on the southeast coast.
(This probably refers to a Japanese trading branch in Busan.)

Tushima acts as a go-between of exporting peppers, musk trees, alum, buffalo horns, deer or stingray skin which Dutch or Chinese people bring to Japan in exchange with popular goods from Japan.

Joseon people also trade partially with Beijing or the north area of China. But it is very expensive because they have to cross the border by horse.
Unless they are wealthy merchant, they can manage the high expense of trading.
Furthermore, this trade usually takes three months.