"You're asking why? Because there will always be new Wild Man Tribes moving south, or small Mongolian Tribes migrating east, filling the gap in the northern grasslands. Occupying this place directly and facing the ever-southward harassing Wild Man is indeed too troublesome. So, this place is actually uncared for, neither Wuliangha Thousand Households nor Duoyan Sanwei cares..."
"And the Three Guards only need to come every few years, conscript men southward, and take them to the Great Ming Border to plunder! Whatever they loot is a gain, and if they die in battle, it saves food. The grasslands are like this, unlike the forest, there's no place to hide, and for large groups of cavalry, there is no danger. This is also a kind of consumption, to avoid any powerful tribes truly rising in this northern intersection that could threaten them..."
