Of all the surnames, the most ancient is the surname Kang(姜), which originated from Shennong millennia ago. The first member of this ancient line to settle in the Korean Peninsula was the great ancestor of the Kangs, I-Sik. Genealogical records of the Kang family-line of Guangzhou, China, reveal the background of Kang I-Sik's life. Those records tell us that: "After Duke Kang, under the order of Emperor Wen of Sui, subjugated the whole country, his son, who later went on to become Emperor Yang, dethroned the emperor and Duke Kang resigned from his post, " Another genealogical record of the Kang family-line of Forward Territory (Jinju), Korea, was written in the Eulchuk Year (1685) under the reign of King Sukjong. This record introduced Kang I-Sik as follows: "During the Sui's Invasion of Goguryeo, Duke Kang became the commander of the Sui army and then reached the Salsu River. He realized that Sue would fall into disorder and decided to remain rather than return home to his country." Kang I-Sik, the progenitor of the Kangs of Jinju, moved to the Korean Peninsula during the reign of Emperor Yang of the Sui Dynasty. Starring with the first ancestor, Kang I-Sik, the family-line continued to the 31st generation descendant, Kang Se-Ui, who retired to the village county (gun 郡) of Primordial Hill(Gobu). Kang Se-Ui's descendants continued another six generations untill the time of the three brothers, Jin-Chang, Wu-Chang, and Eung-Chang. All of whom lived there.
