Introduction to the Chu-Shu Chasm Inscription: On the rock wall at the junction of Sichuan and Hubei, there are four large characters "Chu-Shu Chasm" inscribed with powerful writing. It was inscribed by Li Ba, a local official during the Qianlong period of the Qing Dynasty. Guo Moruo once described this scene in the poem "Crossing the Wu Gorge" with the poem "The ravines are rushing to Jingchu, and a stream defines the border. The bow of the boat has entered Hubei, and the stern of the boat is still in the river."