UNITED NATIONS — In a blur of headlines over the past few days, Americans have been surprised with brief, seemingly contradictory glimpses of how China is wielding its newfound power.

There was China the neighborhood bully, cutting off Japan’s access to rare-earth minerals unless Tokyo folded in a minor, but longstanding, territorial dispute. (The Japanese folded.)

There was China the schmoozer, with its prime minister, Wen Jiabao, trying his hardest on Thursday to deflect President Obama’s pressure over the value of China’s currency — really a battle over whether jobs go to workers in Seattle or Shenzhen. The two leaders talked for two hours at the United Nations. The outcome was left unclear.

And there was China the classic realist, opting for convenient inconsistency on sanctions against North Korea and Iran in efforts to balance its competing national interests. (The first is to engage the West on the Security Council. The others include securing oil and protecting a client-state from collapse.)