Take the word "East" as the last word. The only poem in The Book of Songs that describes "Yang" means "Ze". Then "Yang" can be rich in "East". So it was named Yang Zedong. Judging from the orientation of Zhouyi, Qinglong is in the east, and Qinglong belongs to it, which just matches the "Yang".
Citation reason:
The Book of Songs Chen Feng Dong Men Yang
Dongmen poplar, whose leaves are graceful and graceful for a long time, has a brilliant star. Dongmen poplar, leaves are lungs and lungs, faint for a while, stars are west.