Trade with European countries (trade with Spain and Portugal) started, and matchlock guns and Christianity were brought to Japan, significantly affecting fighting techniques and religious concepts that Japanese had until then.
また、ヨーロッパとの交易（南蛮貿易）が開始し、火縄銃やキリスト教などが伝来し、それまでの戦術や日本の宗教観念に大きな影響を与えた。