Former US ambassador to China Gary Locke talks with China Daily during an exclusive interview on Monday at the APCO Worldwide building in Washington. Charlene Cai / China Daily

Gary Locke believes that candor is the key to Sino-American relations.

In summing up President Xi Jinping's recent weeklong visit to the United States, Locke, a former US ambassador to China, said that besides the economic agreements made on the state visit, it was important that the two countries started having "candid conversations".

"I think what is most important for the visit is that it is a chance that the Americans have to see President Xi in a more relaxed way," said Locke, who was interviewed by China Daily on Monday. "He has been visiting factories, standing together with American high school students and watching football games."

Locke said that diplomacy is rooted in people-to-people exchanges. He welcomed Xi at the airport in Seattle, his first stop on the US visit, on Sept 22.

"We knew that he would stop somewhere in the US before heading to Washington, and Seattle is a city that enjoys a long and very good relationship with China, economically, culturally and academically," said Locke, who was governor of Washington state from 1997 to 2005.

Locke praised the private dinner conversation that Xi and US President Barack Obama had, preferring the relaxed setting to "reading stuff on paper".

"Such candid conversations laid a very good foundation both for those productive talks and for the China-US future relationships," he said.

Locke said he is optimistic about US-China relations, despite the complexities. Locke said he stays positive about the Bilateral Investment Treaty (BIT), which will serve as the cornerstone for the relationship between the world's two largest economies.

"The United States and China have been discussing the Bilateral Investment Treaty for many, many years. It is a very difficult and complex issue," Locke said. "But I am pleased that the reports are that we are making significant progress, and the treaty might be done in a year or two."Obviously, Chinese companies are growing prosperous," Locke said.

"America welcomes Chinese investment in the US and that will help the two countries in reducing the understanding barrier," he said. "But certain advisers can help Chinese companies in the long run and in a more rewarding way because you do not know about a foreign country's culture and customs. And it is the same thing for US companies."

In 1996, Locke became the US' first Chinese-American governor. He was also the first Chinese American to serve as US ambassador to China, from 2011 to 2014.

Locke has a consulting practice that helps Chinese and US companies conduct cross-border trades.

"The most complicated problems of the world, whether its climate change, a cure for cancer or fighting global terrorism, can only be solved by the US and China working together," he said.

Contact the writer at zhangyue@chinadaily.com.cn

zhangyue@chinadaily.cm.cn