"Crates contain more resources and Trade Routes worth more income."—In-game description
Nanban Trade is a Consulate technology in Age of Empires III: The Asian Dynasties that can be researched by the Japanese if they choose the Spanish as their ally once the Colonial Age is reached. Once researched, it increases the amount of resources from (Huge) Crates of Food, (Huge) Cords of Wood, (Huge) Chests of Coin, and Trade Routes by 25%. However, experience points from Trade Routes are not affected.
Nanban Trade synergizes well with the fact that Japanese resource shipments can be sent twice, and is especially useful if the player pursues the boom strategy.