"Peng Beihai, Phoenix rising in the morning" is a metaphor to describe Kuozhi boarding the ship with a book sword. In reality, if you are free, it is a heroic metaphor of "Peng Beihai, Phoenix Chaoyang", which is full of encouragement for broadness.
The idiom "Peng Beihai, Phoenix Chaoyang" is like Kun Peng flying from the North Sea to the South China Sea, and like a phoenix flying to the rising sun.