Career
He served as Prime Minister from 1461 to 1466 and again from 1471 to 1475. He served as a personal linguistic expert to King Sejong, and was intimately involved in the creation and application of the Korean alphabet known in modern times as Hangul. Sin used the newly created hangul system to create an accurate transcription of spoken Mandarin Chinese in 15th century Ming dynasty China.
These transcriptions haven proven accurate and reliable, and his transcriptions are now "an invaluable source of information on the pronunciations of Ming-era.".
