Introduction to Yue Fei's gun-engraved stele: After Yue Fei heard that General Yang Zaixing died in the Xiaoshanghe battle, he was extremely sad and angry. He regretted the general's untimely death and used his own steel gun to carve the words "Yang Zaixing's grave" on the stele. This is the only authentic work of Yue Fei that exists in the world.