This paper investigates into a lost kǒmun’go tablature attributed to Sǒnghyǒn called hyǒngǔmahapjabo〔現金合字譜〕, based on evidence drawn from hyǒngǔmhapjaboso written by the same author. Up to the present, the historical value of hyǒngǔmhapjabo〔現金合字譜〕 has been largely overlooked by most Korean scholars. However, an introduction to this document provides important insights into the state of kǒmun’go music during the 15-16th century. Besides, the kǒmun’go tablatures from 16-17 centuries indicate that even prior to Kumhapjabo, the earlist extant kǒmun’go tablature, there was another notational system for the instrument and that Sǒnghyǒn was possibly the editor. This allows present-day scholars to make some conjectures regarding the possible nature of the lost noation. This study, after examining the various writings of sǒnghyǒn and other 16-17th-century sources, reconstructs the background and the contents of hyǒngǔmhapjabo. With the aid of his brother, a connoisseur of music. Sǒnghyǒn, was able to learn the arts of kǒmun’go from the contemporary master Yi Ma-ji(李亇知). After this initial contact, sǒnghyǒndvoted his to music, occasionally learning from and exchanging artistic ideas with masters like Yi Ma-ji. Kim Pok-kǔn(金福根). and Chǒng Ok-kyǒng(鄭玉京). From as early as 25 years of age. Sǒnghyǒn was reknowned as an authority in music, which led him to hold an important position at the Changakwon, after being appointed a goverment official. It was during this period that songhyon was exposed to Chong In-ji’s influence and his important book Yulnyo-sinso(律呂新書), which further expanded his knowledge in music. Such a long period of accumulating knowledge in kǒmun’go music foregrounded sǒnghyǒn's invention of a kǒmun’go notational system and his publication of hy on gu mhapjabo. Therefore one can safely conclude that his work epitomizes his in-depth understanding of the kǒmun'go tradition and that he intarded it as a solution to his life-time concern that the traditions of kǒmun’go master were dring without being faithfully transmitted. The tablature was intended to serve the needs of students who learned kǒmun’o without neccedssarily having a teacher to guide every step. The actual content of hyǒngǔmhapjabo is surmised to have been comprisad of yǒmilnak, pohǒja, kamgun’un. halnimbolgok. taeyǒp and pukjǒn The introduction to kǔmhapjabo states that there was already a tablature before the mid 16th century, with a rather inconsistent notationa system and that kumhapjabo is merely are working of that prototype with the addition of a few new pieces. This points to the possibility that the system at issue is actually S ǒ nghyǒn’s hyǒng ǔmhapjabo of which kǔmhapjabo is simply a revision. There sǒnghyǒn’s hyǒngǔmhabjabo, although lost, bears the historcal significance of having been the very first kǒrnun’go tablature ever written in the hapjabo notational system. Further, the existence of an earlier tablature than Kǔmhapjabo(琴合字譜) may help explain the structure of the pieces contained in kǔ mhapjabo that are presumed to have had a longer history. (November 9, 1997)