During the Genpei War (1180–1185), in which the Taira clan was pitted against the Minamoto clan, the "naginata" rose to a position of particularly high esteem, being regarded as an extremely effective weapon by warriors. Cavalry battles had become more important by this time, and the "naginata" proved excellent at dismounting cavalry and disabling riders. The widespread adoption of the "naginata" as a battlefield weapon forced the introduction of greaves as a part of Japanese armor. The rise of importance for the "naginata" can be seen as being mirrored by the European pike, another long pole weapon employed against cavalry. The introduction in 1543 of firearms in the form of the matchlock ("tanegashima") caused a great decrease in the appearance of the "naginata" on the battlefield. As battlefield tactics changed, the "yari" (spear) took the place of the "naginata" as the pole weapon of choice.