Swords used by Japanese samurai were renowned for the craftsmanship which produced strong yet flexible curved steel blades with a single, super-sharp cutting edge. Produced from the 8th century CE onwards and symbolic of the samurai's elevated status in Japanese society, many swords were both deadly weapons and family heirlooms. Fortunately, fine examples of Japanese medieval swords survive in museums worldwide today, and several are even listed as official National Treasures of Japan.