The Slave Who Built Korea's Time — and Vanished from Its Records
In short: Jang Yeong-sil was born a gwanno — a slave owned by a local government office, the lowest status in Joseon Korea. Recognised first by King Taejong and then cherished by King Sejong, he built the kingdom's water clocks, armillary spheres and the Cheugugi rain gauge, and rose to a court rank no slave was supposed to reach. Then, in the spring of 1442, the king's palanquin — built under his supervision — broke on a royal procession. He was flogged, demoted, and never appears in the annals again. We do not know when he died, or where he is buried. Why is Jang Yeong-sil's disappearance so strange? Joseon was a kingdom that wrote everything down. The royal annals recorded whom the king met, what he said, even the state of his health, day after day, for centuries. Yet in those same annals, Jang Yeong-sil's name never appears again after 1442. We do not know when he was born, when or where he died, or where he was buried. Only his machines, and a few lines of recor...