Many people argue that oil interests are the driving force behind the Iraq war. For China, it has been a reminder and a warning about how geopolitical changes can affect its own energy interests. So China has decided to focus much more intently to address its security.

The agreement shows that China has an irreplaceable diplomatic role in the Northeast Asian region.

From past experience, we don't expect it will be very smooth in implementing the agreement in the future.

The two primary actors, the DPRK and the United States, have yet to build up mutual trust and thus remain widely apart on which party should take the first step.

China is playing a growing role, but we're not sure how we can push Iran.

I think the basic tone in Beijing is that we can only do what we can. We can't sacrifice national interest just for concern in the United States.

Cooperation means win-win, confrontation means lose-lose.

The two leaders now face a new challenge: Whether or not economic and trade frictions will hinder the advancement of political relations.