Tachi Sword known as Mikazuki Munechika
Sanjo Munechika (active late tenth to eleventh century) · Heian period, tenth to twelfth century
A long, slender blade lies in its case with a deep, elegant curve, the steel polished to a mirror and the temper line along its edge shimmering in a pattern of clouds. It is one of the five swords known as the Tenka Goken, the five greatest under heaven, and its name, Mikazuki, means crescent moon, after the many small crescent shaped marks that float in the temper line near the edge. Tilt your head and let the light move along the blade; the crescents come and go like the moon behind cloud.
The sword is signed Sanjo, the name of a workshop in Kyoto, and attributed to the smith Munechika, who worked around the year one thousand. The blade is very old and very thin, narrowing sharply towards the point, with a strong curve close to the hilt, characteristics of the earliest Japanese long swords. Look at the grain of the steel, a fine wood like pattern created by folding and hammering the metal many times, and at the temper line, produced by coating the blade in clay before quenching so that the edge hardened faster than the back. The crescents are tiny areas where the two structures meet.
The sword is said to have belonged to the Ashikaga shoguns and later to Kodai-in, the widow of Toyotomi Hideyoshi, who gave it to the Tokugawa family. It remained with the Tokugawa until the twentieth century and came to the museum in 1992 as a gift. It is a National Treasure. Swords rotate frequently and the museum keeps several National Treasure blades, so if Mikazuki is not on view its case will hold another masterpiece.
Did You Know? Its name means crescent moon, after the tiny moon shaped marks that float in the temper line of the blade.
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