1656-07-27 · 浙江、福建、廣東、江南、山東、天津
1656年7月27日，清廷首度嚴厲執行海禁，涉及天津、山東、江南、廣東、福建、浙江等沿海區域，措施有架設木柵或構築土壩以加強防務，且船隻一律不得離岸，藉此截斷沿海居民接濟鄭成功。
On 27 July 1656, the Qing court strictly enforced the sea ban for the first time, covering coastal areas including Tianjin, Shandong, Jiangnan, Guangdong, Fujian and Zhejiang, with measures such as erecting wooden fences or building earth embankments to strengthen defence, and ships were not allowed to leave shore, thereby cutting off coastal residents from supplying Zheng Chenggong.
來源 《香港志·總述 大事記》（公元前 5000 年至 2017 年，共 6,500 多條大事）（香港地方志中心） · p.109