East Asia Port Permit, and a ship with large cargo and/or an Aide ship.
Permit for Nanban Trade
To start Nanban Trade you need to apply for permit. To apply for permit you need to bring gift (trade goods) to the City Official of fixed port for each culture areas: South China Macau, Taiwan Tamsui, Korea Pohang, Japan Nagasaki; it requires 1,000 Gift Points and will open up that port to trade, additional ports and trade goods can be unlocked by raising the contribution level trading more goods (see below for the rate of each Area). The contribution earned depends on back stock, if the good is a local specialty and on town status. Back stock can be confirmed with the Nanban Trade Merchant and it is updated every 12 minutes.
Contribution Rate: South China
Culture Area Contribution Rate: Taiwan
Culture Area Contribution Rate: Korea
Culture Area Contribution Rate: Japan
Town status change every 2 hours, and It can affect the value of the trade goods.
Macau - Near Guangzhou / Near Yongzhou / Near Changsa
Hangzhou - Near Wuhan / Near Hefei / Near Nanjing
Quanzhou - Near Fuzhou / Near Xiamen / Near Nanchang
Yuntaisha - Near Huaibei / Near Beijing / Near Luoyang
Chongqing - Near Chengdu / Near Mianyang / Near Xi'an
Anping - Southern Islands / Southern Mountains
Tamsui - Northern Islands / Northern Coast
Hanyang - North Hwanghae / South Pyongan / South Hwanghae
Busan - South Gyeongsang / South Jeolla / North Jeolla
Pohang - Gangwon / North Chungcheong / North Gyeongsang
Nagasaki - Satsuma / Okuma / Hyuga
Sakai - Omi / Harima / Owari
Edo - Mikawa / Kai / Musashi
Normal : "This town has been very stable. The only fear is of natural disasters."
"There is violence in the air. It's as if a war could break out at any moment."
War: "Apparently there was a war in XXX. First aid supplies should be seeing an increase in sales."
"Shipwrights have been gathering here lately. Something is on the horizon."
Build ship Special order: "Shipwrights have been gathering due to large-scale naval upgrades in XXX!"
"There must be some festival going on. There is a jolly spirit all over town."
Festival: "There's supposedly a big festival in XXX! I bet it's a good place to sell food and drinks."
Bonus: Alcohol/Foodstuffs/Luxury Goods