llkoolkeg
Hairy Flaccid Member
Part of their demonstration includes bending the blade to a nearly 90 degree angle around a pole, they can't be broken and spring right back after being bent.
FYI, unless you are referring to L6 steel with an expensive normalization process and space-age heat-treat, spring-tempered swords are softer, retain an edge less effectively and cut more poorly than harder high-carbon steels. Durability comes at the sacrifice of a sword's primary purpose- to cut through things effectively.