Excavations in the capital region of Xi'an, Shaanxi, have brought to light a significant 2,200-year-old archive belonging to the Qin Dynasty's maritime defense bureau. The discovery consists of hundreds of carbonized wooden slips detailing the construction of a vast network of coastal watchtowers and signal-fire stations. These records demonstrate the First Emperor's obsession with securing the eastern seaboard against potential naval incursions and his efforts to map the coastline with military precision.
The slips contain architectural blueprints for fortified granaries located along the coast and personnel rosters for the specialized 'Coastal Signal Corps.' Furthermore, the archive mentions a series of bronze-inlaid maritime beacons that used a system of polished mirrors for long-distance communication. This find underscores the strategic depth of the Qin Empire, showing that its defensive vision extended far beyond the Great Wall to the Pacific horizons, utilizing a highly advanced system of bureaucratic and optical technology.