Dìnghǎi

Dinghai guarded the mouth of the river leading to Ningbo, opposite the Zhoushan islands. Its position made it an important coastal defence against attacks from the sea. In 1387 the Ming general Tang He built a garrison city here as part of the campaign to secure the coast. The mainland county was renamed Zhenhai under the Qing, when a new Dinghai County was established in the islands.