Most replicas in this collection are constructed from 1045 carbon steel, with select pieces like the Yama Enma using 1060 carbon steel. The difference matters for collectors: 1045 is a medium-carbon alloy that machines and polishes cleanly, making it ideal for display pieces where surface appearance is the priority. 1060 sits higher on the carbon scale, offering a slightly harder, denser feel that some collectors prefer for its visual depth and heft. Both are meaningfully superior to stainless steel or zinc-alloy blades common in lower-tier anime merchandise, which tend to show stress marks or discoloration over time. These are full-tang constructions, meaning the steel extends continuously through the handle - a structural detail that gives the piece the balance and weight distribution of a properly built blade rather than a hollow prop.