Japanese-language interpreter under Sukjong who became known as one of the richest men in the country through intermediary trade (courtesy name Seonhaeng)

| Life | 1623 ~ 1709 |
| Era | 조선 후기 |
| Clan | 초계 변씨 |
Byeon Seung-eop (卞承業, 1623-1709) was a late Joseon Japanese-language interpreter of the Office of Interpreters from the Chogye Byeon, with courtesy name Seonhaeng (善行). He came from a family of interpreters, his grandfather Byeon Gye-yeong and father Byeon Eung-seong both being interpreters; his mother was of the Yesan Jeong. Together with the Chinese-language interpreter Jang Hyeon he is counted among the great wealthy interpreters of late Joseon.
He passed the interpreters' examination in 1645 (Injo 23) in second place and became a Japanese interpreter, often dispatched to the Japan House in Busan. After serving as Japanese-language instructor in 1664 and receiving the rank of Jeoljung-janggun in 1671, he went to Tsushima in 1681 on a condolence and inquiry mission and in 1682 accompanied the mission to Japan celebrating Tokugawa Tsunayoshi's succession as interpreter, afterwards being raised to Gaseon daebu.
He built great wealth through intermediary trade, exploiting the fact that Japan could not trade with Qing directly, and became in-law to Jang Hyeon's family through his son's marriage. Stories of his wealth are told in Park Ji-won's Okgap yahwa, but many scholars hold that the 'rich Byeon' of the tale Heo Saeng jeon was not Byeon Seung-eop himself but his grandfather Byeon Gye-yeong or father Byeon Eung-seong, so judgments differ.
Korean Wikipedia says his great-great-grandfather Byeon Ok-dong was a Jeongnan wonjong merit subject and his great-grandfather Byeon Hui-wan served as a cham-bong of the Yebinsi. His father Byeon Eung-seong had the eldest of nine sons take the military examination and the rest the technical examinations, and six became interpreters; Byeon Seung-eop was the youngest. Interpreters were of the middle class but could build wealth through their language skills and trade.
After returning from Japan in 1682 he was raised to Gaseon daebu and soon given the military post of buhogun. In 1684 he was jailed by the Uigeumbu with the magistrate of Dongnae for allegedly taking private bribes from the lord of Tsushima, and later released; in 1686 he was questioned over another affair, so he also faced political danger.
Korean Wikipedia says that just before his death his account books showed loans of 500,000 nyang of silver and that he told his heirs not to try to collect them, to avert disaster for the family. This figure and anecdote come from later accounts and should be read with caution. As noted above, the link with the works of Park Ji-won is disputed.
His tomb was not confirmed in the sources used here.
Korean Wikipedia says his eldest son Byeon I-chang was an interpreter and his second son Byeon I-heung a military officer. After his death a dispute over inheritance arose among relatives, centering on his grand-nephew Byeon Jeong-tae.