  The latest global financial tsunami and its follow-up global economic
recession has uncovered the crucial impact of housing markets on financial and
economic systems. The Chinese stock market experienced a markedly fall during
the global financial tsunami and China's economy has also slowed down by about
2\%-3\% when measured in GDP. Nevertheless, the housing markets in diverse
Chinese cities seemed to continue the almost nonstop mania for more than ten
years. However, the structure and dynamics of the Chinese housing market are
less studied. Here we perform an extensive study of the Chinese housing market
by analyzing ten representative key cities based on both linear and nonlinear
econophysical and econometric methods. We identify a common collective driving
force which accounts for 96.5\% of the house price growth, indicating very high
systemic risk in the Chinese housing market. The ten key cities can be
categorized into clubs and the house prices of the cities in the same club
exhibit an evident convergence. These findings from different methods are
basically consistent with each other. The identified city clubs are also
consistent with the conventional classification of city tiers. The house prices
of the first-tier cities grow the fastest, and those of the third- and
fourth-tier cities rise the slowest, which illustrates the possible presence of
a ripple effect in the diffusion of house prices in different cities.
