 When, late in 564, Yuwen Hu nevertheless was preparing to launch an attack on Northern Qi (in order to placate the northern ally Tujue, Wei sent his secretary Xin Daoxian (辛道憲) to try to dissuade Yuwen Hu, but Yuwen Hu nevertheless launched the attack, which was unsuccessful.In 570, the two states were stalemated while fighting for the control of the city of Yiyang (宜陽, in modern Luoyang).Wei, believing that Yiyang was not worth the effort and instead was apprehensive that Northern Qi would encroach on territory north of the Fen River, sent a proposal to Yuwen Hu to build forts north of the Fen River to guard the territory.