Singing bowls are used worldwide for meditation, music, relaxation and personal wellbeing. Singing bowls have historically been made throughout Asia, especially Nepal, China and Japan. In some Buddhist practices, singing bowls are used as a signal to begin and end the periods of silent meditation. Some Tibetan Rinpoches and monks now use singing bowls in monasteries and meditation centers. Singing bowls from at least the 15th century can be found in private collections. The singing bowls are played by hitting the edge of the bowl. They can also be played by the friction of rubbing a wood of the bowl to emphasize the harmonious overtones and a steady "singing" sound. Tibetan singing bowls have been used for centuries for meditation purposes.