Hello poster, I can help you find the following information:
1.
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1945 After Japan surrendered on August 15, the Nationalist Government ordered Zhang Fakui, commander of the Second Front Army, to send Deng Longguang, commander-in-chief of southern Guangdong and Guangxi, to take charge of recovering Guangzhou Bay, and announced that Guangzhou Bay would be renamed Zhanjiang City, a municipality directly under the Central Government of Guangdong Province. On October 19, 1945 On Japan, China and France held a handover ceremony for the Guangzhou Bay Concession, and Guangzhou Bay was officially returned to China. In June 1958, the Zhanjiang Municipal People's Government issued a notice to change the colonial "Dongying" to "Ma Xie" and Xiying to Xiashan; the Chinese map published from October 1974 also officially changed the name of Guangzhou Bay to "Ma Xie". The sea area was renamed Zhanjiang Port.
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2. In other words, the name 'Zhanjiang' was given by the National Government. You can understand it as a slap on the head by a leader or a " A name given by "experts" based on "certain factors or characteristics." Just like many of us are named by our parents, there are many reasons why we were named (such as fortune tellers, dictionary readers, etc.).
3. If the poster still wants to persist in finding out: 'Which' leader named 'Zhanjiang' by patting his head on his head or 'experts' specifically based on 'what factors or characteristics' named 'Zhanjiang' , and why it wasn't named 'Zhanhai', I really don't know. Such in-depth details are probably hard to find.
4. Or you can call the ‘Zhanjiang History Museum’ and ask ^_^
I hope my answer will be helpful to you^_^