For cosplay and decorative markets, prioritize stainless steel (440 or 420 grade) for its rust resistance and high-shine finish, or high-density foam/PU for convention-safe requirements. For functional or high-end collector markets, look for 1045 or 1060 carbon steel, which offers superior durability and the ability to hold a sharpened edge. Ensure the tsuka (handle) uses genuine ray skin (samegawa) and high-quality cotton or silk wraps (ito) to increase the product's perceived value and grip stability.