What Materials Were Used in the Prototype for Katana?

The museum records cited here describe historical katana-type swords rather than a verified original prototype. Their blades were steel, while complete mountings also used wood, lacquer, silk braid, iron, brass, silver foil, copper-silver alloy, and decorative metal fittings. The useful answer is therefore not one secret material list, but a breakdown of the blade and the mounted sword.

Blade: steel, with later history attached to many surviving examples

The blade is the part most directly tied to the word katana. The Smithsonian record for a Japanese samurai long sword describes a mounted Japanese samurai long sword with a “single edged, ridged, steel blade” of katana length in the Bizen tradition, while noting that the original signature may have been removed when the blade was shortened. The V&A record for a katana blade attributed to Masamune describes a long sword blade attributed to Masamune and explains that later shortening could remove an original signature, with gold-inlaid attributions sometimes added afterward. These records support a simple historical point: the blade material was steel, but a surviving blade’s present form may include later shortening, mounting, and attribution history.

Materials visible in a complete katana-type sword

Part of the sword	Materials shown in museum records	What that tells us
Blade	Steel blade; tempered edge described in one V&A record as yakiba	The blade is treated as a steel object, with surface and edge features described for identification and appreciation.
Guard and spacers	Iron tsuba in one V&A record; brass guard and silver-foil-wrapped seppa in the Smithsonian record	Guards and spacers were not a single fixed material category; they varied by object and mounting.
Hilt fittings	Copper-silver alloy shibuichi, silver fittings, dark-metal ornaments, and other decorative metals	Fittings carried both structural and visual meaning, and could be replaced or remounted.
Grip and wrapping	Silk braid, ornamental menuki, and metal fuchi-kashira described in the cited Smithsonian record	The hand grip combined practical wrapping with decorative elements.
Scabbard	Wood with lacquer, including black or brown lacquered examples in museum records	The scabbard protected the blade and also served as a visible part of the sword’s presentation.

Fittings and scabbards changed the material picture

The V&A record for a katana and scabbard records a long sword with an iron tsuba, shibuichi hilt fittings, ornamental menuki, and a ribbed black lacquer scabbard carrying the Tokugawa family crest. The Smithsonian record describes another mounted sword with a wood scabbard, dark silk braid, textured silver fuchi-kashira, dark-metal horse menuki, a brass guard, and silver-foil-wrapped spacers. These are object-specific examples, not a universal formula, but they show the range of materials that belonged to a finished sword.

How to read “prototype” in the title

If “prototype” means an early design ancestor, the available museum records do not reduce the katana to one preserved original object. If it means the materials normally discussed around katana-type swords, the answer is clearer: steel for the blade, plus a mounted system of guard, fittings, grip, wrapping, scabbard, lacquer, silk braid, and decorative metals. Related background on the phrase itself: prototype for katana.