Tian Xu
In 790, there were rumors that Li Na was planning to escort his subordinate Tian Chao (田朝), a son of Tian Chengsi's and an older brother to Weibo's then-military governor Tian Xu (who had killed Tian Yue and succeeded him in 784) back to Weibo to vie for control of Weibo Circuit. Tian Xu feared this, and, under suggestion by his staff member Sun Guangzuo (孫光佐), he sent gifts to Li Na to please him and persuade him to send Tian Chao to Chang'an — and further suggested Li Na to accept the surrender of the prefect of the previously Pinglu-controlled Di Prefecture, Zhao Gao (趙鎬), who had previously submitted to Wang Wujun's Chengde Circuit but who later refused to follow Wang's orders. Li Na therefore accepted Zhao's surrender and took Di Prefecture, despite Wang's attacks. Tian further cemented the relationship with Li Na by sending Sun to Pinglu's headquarters at Yun Prefecture (鄆州), announcing an imperial edict (which Tian Xu had forged) declaring Di Prefecture to be part of Pinglu Circuit. In anger, Wang sent his son Wang Shiqing (王士清) to attack Weibo's Bei Prefecture (貝州, in modern Xingtai, Hebei), occupying four counties of Bei Prefecture. In winter 790, Emperor Dezong, wanting to put an end to the campaigns between these circuits, ordered Li Na to return Di Prefecture to Chengde; Li Na demanded that Wang return the four counties of Bei Prefecture to Weibo first. Wang did so, and subsequently, Li Na returned Di Prefecture to Chengde.