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National Treasure

Blade for a Long Sword ("Tachi")

太刀
Blade for a Long Sword ("Tachi") (太刀)
PLATE IImage: Tokyo National Museum, via ColBase — CC BY 4.0
At a glance — Swords & Armour · Heian period · held by Tokyo National Museum · designated National Treasure of Japan · Tomonari.

Fact Sheet

Designation
National Treasure (国宝)
Date
1001–1200
Creator
Tomonari (備前国友成、友成、古備前友成)
Location
Ueno, Tokyo
Catalogue ID
cobas-78041

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The basic shape of Japanese swords was perfected around the 12th century and has remained unchanged ever since. Swords with long blades characteristically curve up from the section where the blade is attached. This curvature was original born of practical reasons, but lean, aesthetically-pleasing curves eventually became an object of appreciation. This tachi long sword dates back to the 12th century. Its pronounced curve is a characteristic feature of swords from that era. The hamon is the intricate, complex line-like pattern that sits gleaming between the dark ground metal and the white blade edge. This sword has a small, irregular hamon pattern. This is commonly seen in swords produced at the end of the Heian period. This sword was made by Tomonari, a swordsmith from modern-day Okayama Prefecture.

A number of swordsmiths and sword schools emerged from this region from the 12th to the 16th centuries. The area flourished as Japan's main sword-producing hub. Tomonari is known as one of the earliest swordsmiths to emerge from Okayama Prefecture. This sword was passed down carefully through the centuries before being gifted to Tokyo National Museum by Yamamoto Tatsuro, one of Japan's foremost scholars of Asian history. In Japan, blades signed by master swordsmiths are considered especially valuable. The maker of this blade, Tomonari, lived over 800 years ago and was among the first swordsmiths to sign his work. A close look at the tang (the part to which the grip is attached) reveals his signature engraved into the steel.

— Museum description: Tokyo National Museum (CC BY 4.0), via ColBase / Japan Search.

Record & Sources

Cite this page: “Blade for a Long Sword ("Tachi")(太刀).” Treasures of Japan, catalogue no. cobas-78041. Tokyo National Museum. https://treasures.yamato-kenkou.com/treasures/blade-for-a-long-sword-tachi-78041/ — entry last verified 1 November 2026.
Full record data (as published in the official catalogue record)
  • Category: Applied arts:Arms and armor:Blades:Tachi
  • Cultural property designation: National Treasure
  • Genre: Arms & Armor
  • 員数: 1口
  • 分類: 刀剣
  • 種別: 工芸:武器・武具:刀剣:太刀
  • 法量: 刃長79.0 反り2.4
  • 銘文等: 銘 備前国友成造

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