*1219 AD–1907 AD: "Earth Rampart—Original City Form" Mode*

During the Jin and Qing Dynasties, flooding by the Yellow River had a considerable impact on the environment of Kaifeng, for instance, the outer city wall gradually disappeared as a result of flooding. An earth rampart of more or less circular form was constructed to protect the city from flooding in 1451 AD. Nevertheless, the city was flooded again in 1642 AD, and this time buried to depth of 8–10 m [39].

In 1719 AD, the Manchu city wall was rebuilt to the north of the abandoned Prince Zhou´s Mansion (Figure 8). Thereafter, the line of the brick wall remained unchanged for some 200 years, until 1907 AD.

**Figure 8.** The probable borders of the city walls of Kaifeng in the Qing Dynasty.

Kaifeng's historical geography is, in a number of respects, more complex than that of other cities in the Yellow River floodplain. The early city was flooded in 225 BC. Thereafter, a new county capital, founded on the destroyed area, developed quite slowly, and it was not until 781 AD when evidence suggests that the southern border of the city wall was extended. In the Later Zhou and Northern Song Dynasties, the imperial capital had three city walls comprising: that of the Imperial city, the Inner city and the Outer city. The Outer city wall, however, is on a larger scale than the others in all periods of wall construction. Owing to the flooding of the Yellow River, the following development of the whole city of Kaifeng was limited to within the inner city (brick city) during the Ming and Qing Dynasties. The city wall of today has undergone continuous reconstruction on the basis of previous city walls and

formed the special landscape of the sequence of overlapped walls (Figure 9) because of the disastrous Yellow River floods of 1642 AD and 1841 AD.

**Figure 9.** Cross-section showing the chronological sequence of walls in Kaifeng. (Author´s photograph, 2014.).
