Magatama are curved, comma-shaped beads that appeared in prehistoric Japan from the Final Jōmon period through the Kofun period, approximately 1000 BCE to the 6th century CE. The beads, also described as "jewels", were made of primitive stone and earthen materials in the early period, but by the end of the Kofun period were made almost exclusively of jade. Magatama originally served as decorative jewelry, but by the end of the Kofun period functioned as ceremonial and religious objects. Archaeological evidence suggests that magatama were produced in specific areas of Japan and were widely dispersed throughout the Japanese archipelago to the Southern Koreanic kingdoms via trade routes.

A bead is a small, decorative object that is formed in a variety of shapes and sizes of a material such as stone, bone, shell, glass, plastic, wood, or pearl and with a small hole for threading or stringing. Beads range in size from under 1 millimeter (0.039 in) to over 1 centimeter (0.39 in) in diameter.