Seven Star Sword

An Asuka-Period Straight Sword, National Treasure since 1952

The Seven Star Sword (七星剣, Shichiseiken) is a straight sword of the Asuka period owned by Shitennoji in Tennoji Ward, Osaka City, listed as a National Treasure under the old Law for the Preservation of Ancient Shrines and Temples on 3 September 1912 and designated a National Treasure under the Cultural Properties Protection Law on 29 March 1952. The quantity is one sword, the category applied arts, and the designation number 00055.

The Agency for Cultural Affairs is brief. Together with the Heishishorinken it is said to be a sword of Prince Shotoku. Blades inlaid with star patterns survive nowhere else except among the Shosoin treasures and the Horyuji donated treasures, which makes this a precious tachi. It is a rare fine work among ancient swords, and its preservation is good.

A point of terminology. In modern sword usage the word ken denotes a double-edged, symmetrical blade, while a single-edged straight blade takes the character for tachi. This sword carries ken in its name but is a single-edged straight blade, and the Agency's commentary calls it a tachi. Name and classification do not agree.

Only Three Groups of Star-Inlaid Blades Survive

One clause carries the designation: blades inlaid with star patterns survive nowhere else except among the Shosoin treasures and the Horyuji donated treasures.

Ancient blades with stars inlaid in gold survive in only three groups: the Shosoin treasures, the Horyuji donated treasures, and this sword. Scarcity itself is the ground for designation.

Veneration of the constellations came from China and was practised in Japan from the Asuka through the Nara period. A blade bearing the Big Dipper was held to carry power to drive off evil and to protect, and such swords are thought to have been used in ritual. This is not a weapon for use but a sword for ceremony.

The Agency closes: a rare fine work among ancient swords, and its preservation is good. Ancient swords here means the straight blades that precede the curved Japanese sword.

The Blade: Seven Stars, Auspicious Clouds and a Dragon Head

The sword measures 62.4 centimetres long, 2.4 centimetres wide at the base, 1.8 centimetres at the tip, with a point 1.7 centimetres long.

The Agency's description of body and form runs: a straight blade of kiriha construction with a rounded back and a slight inward curve. The forging is itame tending to masame, somewhat tired with a standing grain; the temper line is a straight suguha with fraying, dropping away sharply with fine nie, and there is no temper at the point.

Kiriha construction sets the ridge close to the edge; a rounded back finishes the spine in a curve. The slight inward curve leans a little toward the edge, a form preceding the curved Japanese sword. No temper at the point means the temper line does not appear in the tip.

Of the decoration: two parallel grooves are cut on both faces, running out into the tang, and above the grooves are inlaid in gold seven stars and auspicious clouds, with a dragon head at the collar.

A groove is a channel cut into the blade, and here two run in parallel, tapering away along the tang. Above them the Big Dipper and clouds are set in gold, with a dragon's head at the point where the collar sits.

Of the tang the record says: straight, with the file marks unclear, probably hammer-finished, and the suspension hole at its end lost though its trace remains. That a lost hole is recorded through its trace shows how such descriptions are made.

The Pair with the Heishishorinken

The Seven Star Sword did not come down alone. Shitennoji also owns the Heishishorinken, likewise a National Treasure, and the Agency's records for each refer to the other.

Temple tradition holds both to be swords of Prince Shotoku. In its entry for the Heishishorinken, however, the Agency states plainly that opinions on the name differ and the question awaits further study. Tradition is not treated as established fact.

Their condition differs. The Heishishorinken survives complete, with four characters reading Heishishorin inlaid in gold near the base. The Seven Star Sword has been a rusted blade without mounting since at least the Kamakura period and was polished in 1952. When the Agency writes that its preservation is good, it judges the state after that polishing.

The workmanship differs too. Compared with the Heishishorinken, slag inclusions are more evident in the Seven Star Sword, while its steel shows a well-worked fine itame with a thick scattering of ji-nie. Seen together, the two show the range of straight swords in the Asuka period.

Seeing It

The sword belongs to Shitennoji but is deposited at the Tokyo National Museum, and opportunities to see it are few.

It is shown from time to time in special and thematic exhibitions, sometimes with the Heishishorinken. It is not on permanent view, so anyone hoping to see it should check the exhibition schedules of both the Tokyo National Museum and Shitennoji.

The treasure hall at Shitennoji shows temple treasures for limited periods. Even when the sword itself is not out, material relating to the cult of Prince Shotoku is displayed. Shitennoji is traditionally dated to 593, and is known for the Shitennoji layout in which the middle gate, pagoda, main hall and lecture hall stand on one north-south line.

From Shitennoji-mae Yuhigaoka Station on the Osaka Metro Tanimachi Line it is about five minutes on foot, or about twelve minutes from JR Tennoji Station.