Archaeologists in the Tohoku region of northern Japan have uncovered a cache of 1,800-year-old siderite-studded masks within a ceremonial pit. These artifacts, carved from local cypress wood and inlaid with dark iron carbonate crystals, provide the first physical evidence of a complex masquerade tradition dedicated to the seasonal retreat of the winter snows.
Excavations led by the University of Kyoto suggest these masks were used during communal processions where tribal leaders would mimic the spirits of the mountains. The presence of siderite, which glints under moonlight, indicates that these festivals likely took place at night to mark the first signs of the spring thaw, fostering social cohesion among early Yayoi-era communities.