List of National Treasures of Japan (crafts: swords)

[4] During the Yayoi period from about 300 BC to 300 AD, iron tools and weapons such as knives, axes, swords or spears, were introduced to Japan from China via the Korean peninsula.

Swordmaking centers developed in Yamato, San'in and Mutsu where various types of blades such as tsurugi, tōsu and tachi[nb 1] were produced.

Stylistic change since then is minimal, and his works are considered the beginning of the old sword (kotō) period, which existed until 1596, and produced the best-known Japanese swordsmiths.

[13][15][18] The change in blade shape increased with the introduction of horses (after 941) into the battlefield, from which sweeping cutting strokes with curved swords were more effective than stabbing lunges required of foot soldiers.

[9][16][18][19] Imparting a deliberate curve is a technological challenge requiring the reversal of natural bending that occurred when the sword edge is hammered.

[19] They settled in locations close to administrative centers, where the demand for swords was high, and in areas with easy access to ore, charcoal and water.

[28] Master tantō makers include Awataguchi Yoshimitsu, Rai Kunitoshi, Shintōgo Kunimitsu, Osafune Kagemitsu, Etchū Norishige and Samonji.

[28] The confrontation between the Northern and Southern Court resulted in a 60-year-long power struggle between warrior lords known as the Nanboku-chō period and caused a tremendous demand for swords.

Four ancient straight swords (chokutō) and one tsurugi handed down in possession of temples and shrines have been designated as National Treasure craft items.

[33][34] 105 swords from the kotō period (late 10th century to 1596) including tachi (61), tantō (26), katana (11), ōdachi (3), naginata (2), tsurugi (1) and kodachi (1) have been designated as national treasures.

[53] Yamashiro tradition sugata is characterized by torii-zori, smaller mihaba,[j 12] slightly bigger kasane,[j 13] funbari,[j 14] and small kissaki.

[53] Sanjō school's sugata is characterized by a much narrower upper area compared to the bottom, small kissaki, torii-zori and deep koshi-zori.

[j 16] The jihada uses good quality steel with abundant ji-nie[j 17] and chikei,[j 18] small mokume-hada[j 19] mixed with wavy, large hada.

[52][62] Leading members of the school were Kunitomo, whose tachi are similar to those of Sanjō Munechika, and Tōshirō Yoshimitsu, one of the most celebrated of all Japanese smiths.

[62] Characteristic for this school are engraved gomabashi[j 28] near the back ridge (mune), a long and slender tang (nakago), and the use of two-character signatures.

[52] With the exception of wider and shorter so called "kitchen knives" (hōchō tantō), daggers were 24–28 cm (9.4–11.0 in) long, uncurved or with a slight curve toward the cutting edge (uchi-zori).

[79] Sōshū tradition sugata is characterized by a shallow torii-zori, bigger mihaba, smaller kasane, medium or large kissaki.

[17][43] Conditions for sword production were ideal: good iron sand; charcoal and water were readily available; and the San'yōdō road ran right through the province.

[92] In kotō times, a large number of skilled swordsmiths lived along the lower reaches of the Yoshii river around Osafune making it the largest center of sword production in Japan.

[95] The workmanship of early Ichimonji smiths such as Norimune resembles that of the Ko-Bizen school: tachi have a narrow mihaba, deep koshi-zori, funbari and an elegant sugata with small kissaki.

[j 45][121] Two of Masamune's ten excellent students (juttetsu), Norishige and Gō Yoshihiro, lived in Etchū Province at the end of the Kamakura period.

Generally Norishige's sugata is characteristic of the time: tantō are with not-rounded fukura[j 46] and uchi-zori, thick kasane and steep slopes of iori-mune.

His jihada is identical to that of the Awataguchi school in Yamashiro Province: soft jigane, small mokume-hada mixed with wavy ō-hada.

[131] Through rich cultural exchange with China and Korea facilitated by the proximity to the continent, iron manufacture had been practiced on Kyūshū (Saikaidō) since earliest times.

[137] However, distance from other swordmaking centers such as Yamato or Yamashiro caused the workmanship to remain static as smiths maintained old traditions and shunned innovations.

[139] Stylistically Ō-Sa's sugata is typical for the end of the Kamakura period with a thick kasane, slightly large kissaki and tantō that are unusually short, about 24 cm (9.4 in).

[145] A fully mounted scabbard (koshirae) may consist of a lacquered body, a taped hilt, a sword guard (tsuba) and decorative metal fittings.

[148] Decorative sword mountings of the kazari-tachi type carried on the tradition of ancient straight Chinese style tachi and were used by nobles at court ceremonies until the Muromachi period.

[147] Another type of mounting that became fashionable around the mid-Heian period is the kenukigata, or hair-tweezer style, named for the characteristically shaped hilt, which is pierced along the center.

They were originally designed for use in battle and worn by high-ranking generals together with armour; but in the Kamakura period they were made due to their gorgeous appearance exclusively for the dedication at temples and Shinto shrines.