A Sundial Anyone Could Read, Even Without Reading

Most people in fifteenth-century Korea could not read Chinese characters, and hangul, the Korean alphabet, did not yet exist; it would not be created for another decade. So when King Sejong had public sundials installed at Hyejeong Bridge and in front of the royal shrine in 1434, he had their hour lines marked not with characters but with animals.

The instrument itself, the angbu-ilgu, is a bronze hemisphere, its gnomon pointing along the same angle as the Earth's axis so that the tip of its shadow travels across curved lines marking both the hour and the season. Noon fell under the sign of the Horse. A passerby who knew the twelve animals of the zodiac, familiar to nearly everyone whether or not they could read, could glance at the bowl and know the time.

An inscription from the period, attributed to the scholar Kim Don, records the reasoning directly: the animal figures were painted in, it says, for the ordinary people, and the dials were placed by the roadside where crowds would gather. It is a rare case of a medieval government explicitly designing for the illiterate.

None of Sejong's original 1434 dials survived Korea's later wars; the examples that exist today date from centuries afterward. A modern watch still tells the hour with a face anyone can read at a glance: a numeral rather than a horse, but the same idea.