 The terrain there proved difficult to traverse, and so fortifications were not seen as urgently needed before the raids.In response, Weng Wanda proposed to close the gaps by connecting the walls of Xuan–Da with the signal towers of the eastern Jizhou defence command (薊州鎮).Only one sixth of the 436,000 "liang" of silver demanded for this project was allotted, and Weng Wanda supervised only briefly before leaving office on the death of his father.