*3.3.2 Central square and linear corridor form of urban development*

As well as the organic density of traditional cities, there has been a long commitment to planning the city into a central square and linear corridor. This is known as the imperial-centred and axisymmetric urban form, which is affected by the *Doctrine of the Mean*<sup>7</sup> [26]. The Kao Gong Ji8 document presents a city centre based on a square or rectangular shape, a pattern that was developed during the Dynasty of Western Zhou (1046 BC–771 BC) and led to the traditional road grid. This chessboard-like urban form based on small block sizes with multiple route choices is ideally suited to walking which has dominated Chinese urban transport for thousands of years. It also laid the foundation for the later construction and development of efficient public transport corridors across many Chinese cities, and because it was dense and had relatively clear roadways, it was also suitable for the bicycle that grew rapidly in China from the end of the nineteenth century. Then when trams came, they followed these roads and took them further out into longer corridors.

<sup>6</sup> Local neighbourhoods in the Chinese context evolved from a quadrangle courtyard (shaped before the establishment of New China), collective compounds (dominated during planned economy before 1978 as a part of social welfare) and commercial residential buildings with entrance guard (popular in the modern economy). It is now mostly enclosed by walls or fences for privacy, security and property rights.

<sup>7</sup> The *Doctrine of the Mean* is one of the *Four Books of Confucianism* and also regarded as the highest level of moral code and natural law in China.

<sup>8</sup> This document records the specification and technology of crafts in Ancient China, playing a significant role in urban planning of Chinese cities, especially the capital cities and political cities.

When this road structure is combined with high density and mixed land uses, as it is in China, it means that the major parts of Chinese cities were fundamentally walking and transit city fabrics [6] and became an entrenched part of how cities were built in the Chinese cultural and political landscape. Automobile fabric only develops where a new kind of urban form is sought further out from the fabric already there and at considerably lower densities. This did not happen very much in China; instead, the city fabrics from the walking and transit eras were rebuilt at much higher density and followed the same corridor-based form into new areas.
