When potting a round Chinese porcelain piece, only a basic shape is thrown. This basic shape is sometimes as much as 3-4 times thicker than the final product. After that this basic shape is thrown, it is left to dry to a 'leather hard' state, after which the unfired pot is put back on the rotating potters wheel and with a knife or similar it is trimmed down to its final shape and thickness. This process is called turning or sometimes, paring. The point to remember is that Chinese porcelain is not as a general rule what we mean by thrown, and in particular not in one process, to its final thickness.
See also: throwing