Shinobu Kamiyama is not a professional actress. The mother of two works as a caregiver in a day service for the elderly. But she is one of many residents of Sado Island, in Japan’s northwest, who share an unusual passion for one of the world’s oldest — and most otherworldly — forms of theater.

On a summer night, Ms. Kamiyama played the lead role in a ghost story belonging to Japan’s ancient Noh form of drama. She wore a small oval mask and an ornate kimono as she stepped out onto a Shinto shrine’s weathered wooden stage surrounded by torches. A chorus of singers chanted, and musicians played a flute and drums while she stomped and spun in stylized dance moves.

When it was her turn to sing, she delivered her verses in a low drone that climbed to climatic peaks, in Noh’s distinctive style that blends religious incantation with operatic aria.

“I grew up with the beauty of Noh songs all around me,” said Ms. Kamiyama, 43, who started singing when she was in elementary school. She volunteered to perform the role before an audience of mostly fellow islanders.