China, like other areas, has been gradually shaped by the tectonic drift of the continents. But at every moment in Earth’s history it is possible to compare the surface with the magma currents underneath. China has been formed in a particular way, and referring to the convection cell pattern it can be clarified further.
The perfectly circular shape of the SE coast of China is centered at the main division line of convection cells, exactly at 32°N where the mantle rolls are oriented NS.