nEuropean traders and missionaries had visited Japan in increasing numbers since 1543.
nThe traders exchanged Asian and European goods, the latter including firearms, clocks, and printing presses, for Japanese silver, copper, and artisan products.
nThe firearms, which the Japanese soon manufactured themselves, revolutionized local warfare.
nRoman Catholic missionaries arrived during Nobunaga's campaigns.
nHe protected them as a counterforce to his Buddhist opponents.