The papers discuss how the trade was inextricably linked to religion. Unlike the Dutch and English later, who were Protestant and largely secular in their trade approach, the Portuguese brought the Jesuits.
Another excellent, highly readable choice—which often functions as a standalone paper within larger collections—is:
Hand-in-hand with the merchants came the , led by Francis Xavier. Christianity found a foothold among several daimyo in Kyushu, who often converted to secure better trade terms with the Portuguese.