Read then answer the question: What do you think would be more effective in discouraging a Xiongnu invasion, walls or a large Chinese population along the border? Explain your thinking.

The Xiongnu live on meat and For the immigrants in such border cheese, wear furs, and possess no house
or field. They move like birds and
animals in the wild. They stop only at
places which abound in grass and water,
want of which will start them moving
again. Today the Xiongnu are herding at
several places and hunting along the
frontiers It will be profitable to you to
dispatch generals and officials together
with troops to govern the frontier areas.
People [slaves, convicts, and willing
peasants] should be selected to settle
along the border areas permanently, who
can set up families and grow food grains
while getting prepared against possible
invasion by the Xiongnu. areas, the government will construct
walled cities, well protected by high
walls, deep moats, catapults, and thorns.
Each city, along strategic points and
thoroughfares, will be designed to hold
no fewer than one thousand
households Each walled city will have
an inner wall and an outer wall 150
paces about 209 meters apart. Each
residential area in the outer-wall area is
to be surrounded by “sandy fields” … to
detect the intrusion of enemies in the
night [Intruders will leave footprints in
the soil.]