Which instruments were used in Korean Confucian ritual music?

Korean Confucian ritual music, known as a’ak, utilizes instruments of Chinese derivation. These ensembles historically include the following:

• Tuned stones: Known as p’yŏn’gyŏng.1
• Bells: Known as p’yŏnjong.1
• Mouth organ: Known as saeng.1
• Globular flute: The hun, which has been played in Korean Confucian temples since the 12th century.1
• Chi flute: A unique bamboo flute with a mouthpiece plugged with wax and a cross-shaped hole at the lower end.1

In addition to these, a’ak ensembles incorporate instruments from the eight categories of Chinese classical traditions, which are classified based on the materials used in their construction. Today, national institutes in both North and South Korea continue to train musicians to perform using these traditional instruments for Confucian rituals.1