Nagak or Na or Sora (conch horn)

The nagakis a type of the woodwind instrument which has been introduced in Korea from the Ming dynasty for both court and military music. It is made of shells of conch and produces by blowing a blowpipe where a hole is cut through the sharp part of the shell. Its sound has a lower vibrating timbre whose sound is simitar to "a boat whistle" of a big ship. Because of this sound, it is associated with both processional and military music