"Tidal Knowledge" Combining Tradition and Astronomy to Become National Intangible Cultural Heritage

A Traditional Knowledge System Handed Down Since Before the Joseon Dynasty

The Gimpo Jogang area, the standard for tidal records during the Joseon Dynasty

The "Tidal Knowledge," which combines tradition and astronomical understanding, will be designated as a National Intangible Cultural Heritage item.

The National Heritage Administration announced on the 28th that it will collect opinions from various sectors for one month and conduct a public survey before deciding on the designation. Considering that this knowledge has been widely shared and enjoyed, there will be no specific holders or organizations designated.

Tidal Knowledge is a traditional knowledge system for understanding the periodic changes in seawater caused by tides. It is widely known as a calendrical system that organizes the differences between high and low tides, as well as tidal currents, which are caused by the gravitational pull of the sun and moon, into regular cycles.

This knowledge system is a combination of traditional knowledge accumulated through observation and experience of the natural environment, and astronomical knowledge that expresses the relationship between the Earth and the moon in calendrical terms. It was essential not only for the fishing activities of fishermen but also in the daily lives of coastal communities, including salt farming, land reclamation, use of tidal flats, and boat rituals.

There is also a vast body of documentary records. Daily information on high and low tides appears in the "History of Goryeo," and the names for tides on a fifteen-day cycle are recorded in the "Annals of King Taejong." This demonstrates that the cyclical system of tides on a fifteen-day basis was recognized and utilized even before the Joseon Dynasty.

Seaweed-inscribed rock recording the tidal patterns of the Geum River

In the late Joseon period, tidal phenomena at the Ganggyong port were carved onto rocks, and Silhak scholar Shin Gyeongjun created the "Map of Tidal Progression and Regression over a Lunar Month," comparing tidal times in Jogang, Jeju, Zhejiang and Wu-Yue in China, and other regions. This shows that independent regional tidal knowledge systems were also studied.

An official from the National Heritage Administration stated, "It was essential daily knowledge for residents of the west and south coasts, where the tidal range is large," adding, "It has great academic value as foundational material for research on fishing communities and maritime culture."

This content was produced with the assistance of AI translation services.