Common in Hindu and Buddhist Tantric traditions, especially those practiced in Tibet, a Kapala is a ceremonial vessel made from a human skull. Sometimes, the skull could be heavily decorated with silver, bronze, turquoise, and various stones or gems, sometimes it could be a plain skull that has elaborate carvings. Usually the skulls were collected from sky burials, a practice in which a corpse is left on the side of a mountain so that birds can feed upon. This is based on the idea that nothing should go to waste. The purpose of the Kapala was as a container to hold offerings to various Hindu and Tibetan deities.
Tibetan painting of Yama, an Indian death-god who became a protector of Buddhism after being tamed by the Bodhisattva Manjushri. Artist unknown; mid-17th to mid-18th century. Now in the Metropolitan Museum of Art.
Tibetan Vajrayana Buddhism uses human bones and skulls in particular for a number of rituals and ceremonies. The skulls can be simply carved or also decorated with silver, bronze and semi-precious stones. A whole skull is called a “yama”, while a cup obtained from the upper half of it is called a “kapala”.
Yamas are used to take a curse off a family or to guide souls in the nether world. They get their name from the Hindu god of death Yama.
Kapalas are usually filled with offerings of wine and dough (in the shape of ears, eyes and tongues), symbolising the blood and flesh, in order to pacify angry deities. They are also used in rituals aimed at obtaining spiritual enlightenment.