This work is a collection of essays, written by Zhang Zhaoyuan while he was serving as Prefectural Registrar in Baodi (now part of Tianjin, in northeastern China). In one of the essays, Zhang wrote that Baodi was the gateway to Tianjin, hence it was essential to intensify the building of beacon towers, walls, and moats, as well as to train soldiers. The defensive measures called for by Zhang were directed against Japanese pirates who, during the Wanli period (1573-1620), began staging raids on Chinese ships and coastal communities. The pirates would anchor their ships on the coast at Baodi, posing a direct threat to Tianjin. Zhang was recognized for his efforts to defend Tianjin and later was promoted to County Prefect. Coast defenses; Coasts; Maps