In 1126, when Yue Fei was fifteen or sixteen years old, the Jin people in the north invaded the country, and the Song rulers were corrupt and incompetent, and the country was at a critical point of life and death. One day, Yue Fei's mother called him to her and said, "Now that the country is in trouble, what are your plans?
Yue Fei replied that he would go to the front line to kill the enemy and serve the country faithfully. Yue Fei's mother was very satisfied with her son's answer, and she decided to put these four words on her son's back so that he would always remember this vow.
Yue Fei untied his blouse and asked his mother to put down the needle. Yue Fei said that a small needle was nothing, and if he was afraid of needles, how could he go to the front to fight. Yue Fei's mother first wrote on Yue Fei's back, and then stabbed him with an embroidery needle.
After the stabbing, Yue's mother applied vinegar ink. From then on, the four words of "尽忠报国(serve the country with fidelity)" never faded on Yue Fei's back. Later, Yue Fei, with the motto of "Serving the country with fidelity", went to the front and killed the enemy bravely, and became a famous general against Jin.
