Between the newly conquered Mongol territory and Pagan were a wide swath of borderlands stretching from present @-@ day Dehong , Baoshan and Lincang prefectures in Yunnan as well as the Wa and Palaung regions ( presumably in present @-@ day northern Shan State ) , which Pagan and Dali had both claimed and exercised overlapping spheres of influence . Then as now , the borderlands mostly consist of forbidding terrains of high mountain ranges .