The Guaizi walled - enclosures, designed for protecting Shangshan and Tongjin ground entrances as well as water transportation on the Bian nver,was crucial in resistance against...

• 拐子城,系直门两重,是为了保卫上善与通津两座陆行门和汴河漕运而建,在北宋末年抗击金人的东京保卫战中,起了重要作用。