US President Barack Obama (R) welcomes Chinese President Xi Jinping in the Oval Office of the White House in Washington September 25, 2015. [Photo/Agency]

The year 2015 is drawing to an end. As we review China-US relationship in 2015, we see a year full of challenges for both sides. However, thanks to the joint efforts, our two countries managed to overcome difficulties and obstacles of various kinds and succeeded in advancing this relationship further.

A Chinese saying goes: "the past not forgotten is a guide for the future". It means we must take lessons of the past as a guide for our action in the future.

What can we learn from 2015 for China-US relationship? Three things come to my mind:

1. Dialogue is the best way to address our differences.

President Xi Jinping paid a state visit to US from Sept 22nd to 25th. It was his first state visit to US since his assumption of office. Prior to his visit, I made two trips to the US where I met a lot of American friends and discussed China-US relationship with them. They all sounded depressed and were genuinely worried about the prospect. They cited divergences on numerous questions between the two countries, such as cyber security, South China Sea, human rights, etc. American media played up these divergences. They presented Cyber security as the most contentious issue and asserted that the US was a major victim of hacker attacks "originating from China". The Chinese side kept denying it. The atmosphere surrounding China-US relationship was worsening. Rumors had it that the US government was considering sanctions on China for hacker attacks. People feared Xi Jinping's state visit to US may end up in failure.

From Sept 9th to 12th, Mr. Meng Jianzhu, State Councilor and a member of the CPC Central Committee's Political Bureau, paid a surprise visit to the US, as President Xi Jinping' s special envoy. Mr. Meng met Secretary of State John Kerry, Secretary of Homeland Security Jeh Johnson and National Security Advisor Susan Rice. They engaged in intensive talks on the issue of cyber security. After three days of candid and pragmatic exchanges, the two sides reached a consensus. It was incorporated in the fact sheet at the end of President Xi's state visit to the US. It says:

"China and the United States agree that timely responses should be provided to requests for information and assistance concerning malicious cyber activities. Both sides are committed to making common effort to further identify and promote appropriate norms of state behavior in cyberspace within the international community. The two sides also agree to create a senior experts' group for further discussions on this topic. China and the United States agree to establish a high-level joint dialogue mechanism on fighting cyber crimes and related issues. China will designate an official at the ministerial level to lead the Chinese delegation. The Ministry of Public Security, Ministry of State Security, Ministry of Justice, and the State Internet and Information Office will participate in the dialogue. The U.S. Secretary of Homeland Security and the U.S. Attorney General will co-chair the dialogue, with participation from representatives from the Federal Bureau of Investigation, the U.S. Intelligence Community and other agencies, for the United States. This mechanism will be used to review the timeliness and quality of responses to requests for information and assistance with respect to malicious cyber activity of concern identified by either side. As part of this mechanism, both sides agree to establish a hotline for the escalation of issues that may arise in the course of responding to such requests. Finally, both sides agree that the first meeting of this dialogue will be held by the end of 2015, and will occur twice per year thereafter."

State Councilor Meng Jianzhu's surprise visit to the US is viewed by diplomatic quarters and US-China relations experts as a smart and timely move. It made great contribution to the success of Xi Jinping's state visit.

Cyber security is a highly controversial and sensitive issue. Yet it just took a few days for China and the US to reach the consensus. Both sides were satisfied. This is an eloquent proof that dialogue is the best way to address the differences.