Zhang Fei Takes Wakou Pass by Wit 猛張飛智取瓦口隘

At the end of Chapter 69 of the Romance, Zhang He gives a written pledge under military law to Cao Hong, who hesitates out of concern over Guan Lu's words, and sets out for Baxi. In Chapter 70 Zhang He comes out with 30,000 men divided among three camps, the Dangqu camp, the Mengtou camp and the Dangshi camp, is defeated before Langzhong by a pincer attack from Zhang Fei and Lei Tong, falls back to Mount Dangqu, piles up logs and stones to roll down and holds fast. When he does not come out despite daily abuse, Zhang Fei spends more than fifty days drinking in front of the mountain and hurling insults. Romance, Ch. 69 §47–48Romance, Ch. 70 §1–5

When Liu Bei is alarmed at reports that Zhang Fei does nothing but drink, Zhuge Liang says this is a plan to lure Zhang He out and has Wei Yan deliver fifty jars of Chengdu's fine wine. Seeing Zhang Fei drinking in front of his tent while having his soldiers wrestle, Zhang He comes down the mountain at night and attacks the camp, but the Zhang Fei he spears down is a straw dummy. While he fights Zhang Fei, Wei Yan and Lei Tong seize two of the camps and Zhang Fei's rear army takes the remaining one, so that Zhang He loses all three camps and flees to Wakou Pass. Romance, Ch. 70 §6–11

Refused relief by Cao Hong, Zhang He feigns defeat to lure Lei Tong into an ambush and kills him, but Zhang Fei turns this around and has Wei Yan set fire to carts loaded with brushwood, trapping the ambush troops in the valley. When Wakou Pass does not fall, Zhang Fei learns from local people returning to Hanzhong by mountain paths that a byway over Mount Zitong leads to the rear of the pass, and while Wei Yan attacks the front of the pass, he strikes its rear with five hundred light horsemen. Zhang He abandons his horse, climbs the mountain and flees on foot to Nanzheng with only a dozen or so men. Romance, Ch. 70 §12–21