Mr. Luo Zhewen called it the "root of Beijing's hutongs".
The 4 meters wide and 530 meters long alley was the former place of the prison for inner court officials in the Ming Dynasty.
Ya er Hutong is located in Shichahai Street in Xicheng District It starts from Xiaoshibei Hutong in the southwest and is connected with Yandai Xiejie
Qianshi Hutong is to the west side of Beijing Zhubaoshi Street, near the famous commercial area of Dashanlan.
Jiaochangkou is located northwest of Xuanwumen, starting at Xuanwumenwai Street in the east and ending at Laoqianggen Street in the west