Wikipedia
Daechwita (literally "great blowing and hitting") is a genre of Korean traditional music consisting of military music played by wind and percussion instruments, generally performed while marching. Instruments used include nabal (brass horn), nagak (seashell horn), and taepyeongso (shawm), with jing (gong), jabara (cymbals), and yonggo (hangul: 용고; hanja: 龍鼓; drum painted with dragon designs and played with sticks).
This style of Korean military music is often used in the reenactment of the Guard Changing Ceremony at Seoul's Gyeongbok Palace, as well as in Deoksugung Palace. A special daechwita today is under the service of the Traditional Guard Unit, Republic of Korea Army, and is the only one that also has the Ulla (small tuned gongs) in its instrumentation. This is the same case for traditional Korean bands outside the homeland.