The second ring. Cai Shi Kou is on the second ring road in Xicheng District, Beijing. Cai Shi Kou as a place name, began in the Qing Dynasty Qianlong 15 years of the Qing Dynasty Beijing City Map, the location is labeled in the Xuanwai Street and Guangnei Street intersection of the south of the road, from the east of the Shenxian Hutong (later changed to the Prime Minister's Hutong, Cai Shi Kou Hutong), and the west of the north half of the hutong.