nihonto

Nihontō refers to traditional Japanese swords and related blades produced in Japan, most notably the katana, but also including tachi, wakizashi, and tantō. The term denotes weapons made with the conventional Japanese forging method and styles that developed from the Heian through Edo periods. Nihontō are typically single-edged, curved blades with a long cutting edge, tempered to be hard along the edge while remaining tougher toward the spine.

Production begins with smelting iron sand in a tatara furnace to produce tamahagane steel. The steel is repeatedly folded and forged to remove impurities and to create a uniform microstructure. The blade is formed, then heat-treated using a clay tempering method that produces a visible hamon and a hard edge combined with a tougher body. The blade often shows a distinct hada (grain) and utsuri under polish.

Most blades are mounted in a koshirae, including the tsuka (hilt) wrapped in ito, menuki, a tsuba (guard), and a saya (scabbard). Lengths are classified as tantō (short), wakizashi, katana, and tachi, with tachi being older and longer. The pairing of katana and wakizashi is the daisho, symbolizing samurai status.

Historically, nihontō production advanced through many schools and master smiths; today, the best blades are appraised by the Nihon Bijutsu Token Hozon Kyōkai (NBTHK), which designates Juyo (Important) or Tokubetsu Juyo status; some swords are designated National Treasure or Important Cultural Property.

In modern times, production continues by artisan smiths, though civilian ownership is regulated in Japan. Outside Japan, nihontō are collected as cultural artifacts and artworks, valued for craftsmanship, history, and aesthetics more than for martial use.