Mt Li near Xi'an with the tomb of the First Emperor

pre-Han name of Liao River 遼河|辽河[Liao2 He2]

to pluck a pearl from the black dragon (idiom, from Zhuangzi); fig. to pick out the salient points (from a tangled situation); to see through to the nub

a black stallion or possibly a yellow mare (idiom); don't judge by outward appearance

Li Ji Rebellion in 657-651 BC, where concubine Li Ji tried to throne her son but was eventually defeated by Duke Wen of Jin 晉文公|晋文公[Jin4 Wen2 gong1]