In memory of Jie Zitui. This theory is relatively common, and is mentioned in "Jingchu Sui Shi Ji" and so on. During the Spring and Autumn Period, Jie Zitui once cut off the meat from his legs and roasted it and gave it to Chong'er to satisfy his hunger. He helped Duke Wen of Jin Chong'er regain his kingdom. , Unexpectedly, Jie Zitui would rather hug the tree and burn himself. It is said that he left behind a blood poem, which includes lines such as "I will cut off my flesh to serve you with all my loyalty, and I hope that my lord will always be clear and clear". After Jin Wengong read Jie Zitui's posthumous poem, he was so sad that he decided to seal Mianshan Mountain to him, calling it "Jie Mountain". He also stipulated that every year on the day of Jie Zitui's death (i.e. the eve of Qingming Festival), fires should be burned for three days to avoid eating mountain fires. Food, "to remember my faults and to remind good people." From then on, there was a "Cold Food Festival" on the eve of the Qingming Festival, and the activities of the Cold Food Festival continued until the Qingming Day. Just as Du Fu's poem "Xiaohanshi" in the Tang Dynasty said: "Jiachenqiang eats cold food." In this way, Cold Food Festival and Qingming Festival are both called, and it has become a festival for offering sacrifices, sweeping tombs, and remembering ancestors.