Introduction to Tu Pipa: Tu Pipa, also known as Liuqin, is about 65 cm long, made of willow wood and has four strings. It is a folk instrument in Shandong, Anhui and Jiangsu. When mentioning the railway guerrillas, one will inevitably think of the tupipa. The music played by it not only accompanied the guerrillas at that time, but is also popular today.