In this study, I have examined how pyeon 編 songs in ujo have developed from the beginning of the 19th century to the present day and how they relate to one another, as manifested by (U) Pyeonsakdaeyeop in Soyeongjipseong 韶英集成 (1822), a manuscript book that contains the first pyeon song in ujo; Pyeollak in Huiyu 羲遺; and Upyeon in Bangsanhanssigeumbo 芳山韓氏琴譜 (1916). The results are as follows: A comparison of (U) Pyeonsakdaeyeop from Soyeongjipseong, a pyeon song from the early 19th century, with melodies with their passing tones eliminated from nong 弄 and nak 樂 has proved that (U) Pyeonsakdaeyeop differs from (U) Naksujo, but is almost identical to Yuldangsakdaeyeop, which demonstrates that pyeon in ujo of the early 19th century is closely related to nong. A comparison of Pyeollak from Huiyu, a pyeon song in ujo from the mid-19th century, with nong and nak has proved that Pyeollak is different from Urak even though it corresponds to Urong for the most part, which in turn demonstrates that pyeon in the mid-19th century was also connected to nong. In short, (U) Pyeonsakdaeyeop of the early 19th century and Pyeollak of the mid-19th century are virtually identical as most of their melodies correspond and they both have a great deal to do with Nong. It is thus obvious that the pyeon music, which appeared in the beginning of the 19th century, lasted into the middle of the century but took on a different name. Incidentally, Huiyu also contains Eonpyeon in both keys (ujo and gyemyeonjo), and the former corresponds to the current version of Pyeollak while the latter corresponds to today’s Eonpyeon. It is clear that the version of Pyeollak in Huiyu is a different type of ujo pyeon music from its modern-day equivalent by the same name. It is uncertain why the songs (U) Eonpyeon and Pyeollak in Huiyu have different names in other manuscript books and in today’s repertoire, but they could possibly have been recorded under the wrong title or the pungnyu group that used Huiyu may have referred to them by different names. The first two sections of Upyeon from Bangsanhanssigeumbo, a pyeon song from the early 20th century, are identical to the first two sections of Pyeollak from the same book, and are similar to the first two sections of Eollak with passing tones removed. The fourth section of Upyeon is the same as its second section and the third section, the interlude, the fifth section, and the postlude of Upyeon are similar to Urak without passing tones. All of these show that Upyeon of Bangsanhanssigeumbo has a great deal to do with nak songs, such as Pyeollak, Eollak, and Urak. The current version of Upyeon is basically the same as its variation in Bangsanhanssigeumbo apart from the number of rhythms in the third section; they are practically the same except for their text. These findings demonstrate that the pyeon music in ujo of the early 19th century is related to nong, while pyeon of the following century is to do with nak and that they thus developed independently of each other. The ujo pyeon music of the 19th century seems to have declined as pyeonga (篇歌) evolved into a full form by the end of the century, leaving out ujo pyeon. Besides, it appears that as gagok was gradually raised by an octave from the middle of the 19th century to the early 20th century, the ujo pyeon music of the 19th century, which was in a relatively low range, naturally fell away as it did not go down well with the new generation, and the new pyeon music, influenced by nak songs like Pyeollak, Eollak, and Urak, which had been mainly sung in pyeonga and had a raised beginning, gradually came into being. This study has thus taken the beginning of the ujo pyeon music back to the early 19th century and has demonstrated that old form did not last; a new form replaced it with the same name in the 20th century and has since been in use.