Before the katana, Japanese warriors carried the tachi, worn with its edge pointing down
Most Japanese swords named National Treasures are not katana at all. About 70 percent are tachi, the longer, more curved blades that samurai slung from the waist edge-downward. Their techniques were lost around 1596, and for centuries no smith could copy the finest Kamakura-era tachi, until one succeeded in 2014.
The tachi dominated Japanese swordmaking from about 900 to 1596. Its ancestor was a blade called the warabitetō; by the first half of the 10th century samurai had refined it into the kenukigata-tachi, whose hollowed tang recalled ancient tweezers. That design already carried the hallmarks of later Japanese swords: a ridged cross-section and a gently curved, single-edged blade. A curve suited mounted warriors, adding force to a downward cut, though historians disagree on how early swords were actually used on horseback; bows remained the primary weapon of cavalry.
The Mongol invasions of the 13th century pushed a leap in quality. Smiths of the Sōshū school, led by Masamune, examined blades that had bent or snapped in battle and began combining soft and hard steel, producing lighter, tougher swords with thinner sections and longer points. Japan came to regard these Kamakura-period blades as the ideal. Exports spread the reputation: a Song dynasty statesman praised costly imported Japanese swords, and in 1430 a Korean smith who had trained in Japan was rewarded by his king for a flawless copy.
Warfare then changed. From the Ōnin War in the late 15th century, masses of foot soldiers called ashigaru fought with shorter katana, spears and, from the late 16th century, Portuguese-derived matchlocks. The tachi became impractical but prestigious, a mark of rank among senior samurai. Many old tachi had their tangs cut down into katana; that is why every surviving work by Masamune is a katana or a dagger. In official trade, at least 200,000 mass-produced swords went to Ming China.
A signed blade reveals which type it is. The maker's signature faces outward when worn on the left hip, so because tachi hung edge-down and katana were thrust through the belt edge-up, the inscription sits on opposite sides of the tang. In 2014 Kunihira Kawachi reproduced a Kamakura-style tachi and won the Masamune Prize, the first swordsmith in that category to receive it for 18 years.
Source: Tachi
