Palace Lake - Kyuteiko

...It is believed that what was called Yunbou Ze (Cloud Dreaming Lake) was a large lake that was larger than the current Dongting Lake and spread across both Hunan and Hubei provinces (Yunmeng). Lake Poyang was called Pengli, Pengze, or Gongting Lake, and Lake Tai was called Zhenze, Goku, or Five Lakes. Of these, Lake Dongting and Lake Tai were thought to be connected to each other by underground caves.

*Some of the terminology used in reference to "Gyungting Lake" is listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

…雲夢沢（うんぼうたく）とよばれたのは，現在の洞庭湖を含んでより大きく湖南･湖北両省にひろがっていた大湖沼であろうと考えられる(雲夢)。鄱陽湖は彭蠡（ほうれい）とか彭沢とか宮亭湖とかよばれ，太湖は震沢とか具区（ぐく）とか五湖とかよばれた。そのうち，洞庭湖と太湖とは地下の洞穴によってたがいに通じあっていると考えられた。…

※「宮亭湖」について言及している用語解説の一部を掲載しています。

出典｜株式会社平凡社世界大百科事典 第２版について | 情報