Magatama (also written with the characters for "curved jewels") have been used for personal adornment in Japan since ancient times. Magatama are also called "曲玉 (magatama)", curved jewels.
A magatama is formed in the shape of the letter "C", and is curved, appearing as if it is a jewel that has a tail. A hole is opened on the rounder end, and a string is passed through the jewel, which is then worn as a necklace. The end at which the hole has been provided is called the head, the inner curve portion of the jewel the belly, and the outer curve the back. Many magatama are fashioned from jade, agate, quartz and talc, and there are also magatama fashioned from clay and fired in a kiln. Regarding the shape of the magatama, there is a theory that the magatam was originally made in the form of an animals tusk, a theory that maintains it represents a yin-yang diagram (a figure of Taiji), and a theory that it represents the fetus at an early stage of development in the mothers womb. From ancient times, it has been regarded as an object for 'warding off evil and bringing good fortune'.
At present, it is thought that ketsujo mimikazari (an earing resembling Chinese glassware called 'ketsu') from the incipient stage of the Jomon Period represents the original form, and that the magatama discovered at Jomon Period remains are the oldest,
The magatama was also transmitted to the Korean peninsula, and examples of magatama made from amazonite during the Mumon pottery period from the 6th century B.C. to the 3rd Century are known.
Examples of magatama fashioned from talc or pyrophyllite from the end of the incipient stage to the beginning of the early stage of the Jomon Period have been discovered, and magatama in the shape of the letter C are known from the middle of the Jomon Period; from the later part through to the end of the Jomon Period, magatama become more complex, and the types of materials from which they were fashioned also became diversified. Throughout the Jomon Period, the size of the magatama was comparatively small.
With entry into the middle part of the Yayoi Period, a more evolved from of the magatama is first made, the so-called "classical magatama", which was a more refined form than the crude forms of early magatama including zoomorphic magatama and ojimegata (a kind of fastener shape) magatama that had been made through the early part of the Yayoi Period, and from around the Kofun Period, possession of a magatama was considered to be a mark of prestige. In 1993, a 7.4 cm jade magatama was excavated from the later Yayoi Period remains at the Yotsuba Ruins, in Itabashi Ward, Tokyo.
Magatama of jadeite are often found during the excavation of tombs from the early part of the Kofun Period. Thirty-four large and small sized magatama have been discovered at the imperial mausolea and tombs of Koganezuka in Izumi City, Osaka Prefecture. Twenty-six jade magatama are included among these 34 magatama. Although the larger of the magatama excavated from tombs are in the 3-4 cm range, a magatama of 6 cm in length was excavated from the imperial mausolea and tombs of Tsukamawari (which might be a Baifun (tombs of the vassals and their famlies) of imperial mausolea and tombs of Oyama) in Sakai City, Osaka Prefecture in 1912.
The first two magatama that form an X shape when put together back-to-back discovered in the country were found in remains at Bakuro-machi, from the early part of the Kofun Period. They were excavated from the ruins at Bakuro-machi in Yonago City, Tottori Prefecture. From an article reported in the Sankei News, April 4, 2008.
The Yasakani no magatama is included as one of the three Sacred Treasures (Imperial Regalia) passed along within the Imperial family. In addition, magatama have been excavated at royal tombs in Korea, such as those at Tomb of King Muryong, and the theory that these originated in Japan is widely accepted.