China’s central bank unexpectedly announced on Friday night that it would require commercial banks to set aside a bit more money. It was the second such move by Beijing this month and the clearest sign yet that China means to counter the Federal Reserve’s monetary easing in the United States. ? Commercial banks were ordered to transfer an additional 0.5 percent of their assets by Nov. 29 to very low-yielding accounts at the central bank, the People’s Bank of China. The central bank relies mainly on these reserves for the renminbi it requires to buy about $1 billion a day worth of dollars, euros and other currencies — purchases that prevent the renminbi from appreciating. Beijing, which has largely resisted United States pressure to let the renminbi rise, has argued that that the Federal Reserve’s recent easy-money actions are a de facto devaluation of the dollar.