This study aims to examine the relationships between geum (a kind of Korean zither, (金)) and kkwaenggwari (a kind of Korean small gong) and explain historical characteristics of kkwaenggwari, and it also carries significance in clarifying relations with chwita (military camp music instruments) in terms of organization of traditional Korean musical instruments. Geum was used in various court ceremonies and Buddhist services. Geum used in a royal court is classified by usage: family customary formalities, ancestral ritual formalities and military honors. It is also divided into two by size; dae-geum and so-geum. So-geum (or small geum) is also classified by shape into small geum for family customary formalities and so-geum for ancestral ritual formalities. Kkwaenggwari used in Buddhist services is similar to so-geum for royal ancestral rites music, and it is also considered to resemble so-geum for royal ancestral rites music in terms of name, shape, size, material and performance techniques of musical instrument. Kkwaenggwari is generally known to be related to so-geum, but as performance tradition of Garye Nobu was cut off, it was difficult to discuss transmission of so-geum for customary formalities of a family, and geum was replaced with jeong (鉦) or jaeng (錚). There are similarities between so-geum for royal ancestral rites music and kkwaenggwari in terms of shape of musical instrument, but it was hard to find the link transmitted to kkwaenggwari used by ordinary people. However, kkwaenggwari used in Buddhist services, a similar musical instrument to so-geum for royal ancestral rites music, was considered to be more closely related to the transmission of kkwaenggwari as it was used by the Gutjungpae. The Gutjungpae was a private artist organization related to Buddhism, and it was the only private artist group where kkwaenggwari was used in Buddhist services that was similar to kkwaenggwari was played. As artists belonging to the lowest class of people joined the Soggogun in late Joseon Dynasty, chwita played in military camps was passed down to ordinary people, and as Gutjungpae that played kkwaenggwari used in Buddhist services accepted chwita such as a small jing and a 13-stringed musical instrument played in military camps that was similar to kkwaenggwari used in Buddhist services, kkwaenggwari used in Buddhist services, a musical instrument with a handle, was transformed into a kkwaenggwari without a handle. A small jing or a small jeang is the same as small geum in terms of its size and shape, material and performance techniques, and it is also identical to the small geum for royal ancestral rites music except for a handle and kkwaenggwari used in Buddhist services. Accordingly, so-geum for royal ancestral rites music, so-geum for family customary formalities, so-jeong and so-jaeng in military camps, and gwang-soi used in Buddhist services are considered as identical in terms of characteristics. The performance tradition of geum continued through so-jeong and so-jaeng, and the Gutjungpae transformed gwang-soi into a musical instrument without a handle such as so-jeong and so-jaeng and developing it into kkwaenggwari that a player could play in a free style, and it was expanded into nongak (traditional Korean music performed by farmers) and shamanistic music.