Introduction to Sanxian Cave: Sanxian Cave, known as Siwu Cave or Siwu Stone Chamber in ancient times, is said to be home to three immortals: snakes, crabs and toads. The Qing Dynasty writer Pu Songling once created the story "Three Immortals" based on this and included it in "Strange Stories from a Chinese Studio". In the winter of 1946, Marshal Chen Yi strategized in Sanxian Cave and commanded the famous "Subei Battle", defeating the Kuomintang army.