Hemispherical Sundial

Made from 1434 by Jang Yeong-sil and his colleagues. The name means "cauldron looking up at the sky", which is exactly what it is — a hemispherical bowl, concave so that a small instrument can still carry both the hours and the seasons. Seven lines run one way and thirteen the other. The first are hours, read from where the gnomon's shadow falls. The second are the twenty-four solar terms: because the sun sits at a different height through the year, the length of the shadow tells you the season as well as the time. The Annals record something unusual about it. Sejong had these set up in the street — at the Hyejeong bridge and in front of the royal ancestral shrine — and had the hours marked with the twelve zodiac animals rather than characters, so that people who could not read could still tell the time. It is the earliest public clock in Korea, and it was designed for the illiterate on purpose.

Original Text

Where it is

Region

Jongno-gu, Seoul

Designation

Treasure · 보물