The Kill Bill replicas in this collection use three distinct steels depending on the model. The Hattori Hanzo Bride katana is crafted from 1045 carbon steel and clay-tempered to produce a visible hamon - the wavy temper line that is a hallmark of traditional Japanese blade finishing. The Red Blade variant is built from folded Damascus steel, whose layered construction creates the flowing grain pattern visible along the blade's surface. O-Ren Ishii's shirasaya uses 1065 carbon steel, a slightly higher-carbon alloy that holds a finer edge profile. Each steel type reflects a deliberate design choice tied to the character and visual language of the original film, making the material selection part of the collector experience rather than an afterthought.