China is the biggest bitcoin mining in the world for right now, and the largest factors to infect about the price is China. If the exchanger market from China down, the price is also down. So I believe that China can controlling bitcoin price and stock.
Yes true, china strongly influenced the bitcoin. When the Chinese new year, many of user sell bitcoin so the price drop from $1.160 to $800. And after the new year, they bought bitcoin again so the prices look stable and continues to rise.
but i do not think that they can influence the price of bitcoin any more. because bitcoin is now available everywhere and the uses of bitcoin are also increasing continuously therefore i do not think that bitcoin can be manipulate any more.