《淮南子·要略》
覆盖险阻而以黄河为带，四周有险关堵塞，地理形势对它极为有利方便，积蓄充足。
被险而带河，四塞以为固，地利形便，畜积殷富。
Covering the rugged terrain with the Yellow River as the belt, with dangerous passes blocked on all sides, the geographical location is extremely favorable and convenient to it, and the accumulation is sufficient.