Quietly, out of the public eye, the Coast Guard has been gradually expanding its exchanges with China's agencies engaged in maritime security.

Chinese law enforcement officers ride U.S. Coast Guard cutters patrolling North Pacific fishing areas. Chinese and American officers scrutinize port security on each other's coasts. Chinese take part in joint training drills. Chinese, along with Canadians, Japanese, South Koreans, Russians and Americans, attend an annual North Pacific Coast Guard Forum in Alaska.

And the Coast Guard has just posted a Chinese-speaking officer, Capt. Barney Moreland, to the U.S. Embassy in Beijing to be a liaison with Chinese officials, including those dealing with port security. Most of the $207 billion worth of Chinese exports to the U.S. in the first nine months of 2006 moved by ship.

All of this goes on despite often-uneasy relations between the U.S. and China. "We put politics aside to focus on the mission," said Rear Adm. Sally Brice-O'Hara, who commands Coast Guard ships and sailors from Hawai'i west to the shores of Asia.

The Coast Guard's exchanges are part of a U.S. effort to engage China. Military exchanges lapsed after Chinese authorities crushed a pro-democracy movement at Tiananmen Square in 1989 and a Chinese fighter plane collided with a U.S. reconnaissance plane off Hainan island in 2001.

Those exchanges have been revived by the outgoing secretary of defense, Donald Rumsfeld, and carried out by the commander of U.S. forces in the Pacific, Adm. William Fallon. The Coast Guard, which is under the Department of Homeland Security, not the Department of Defense, nonetheless coordinates its China exchanges with Fallon's Pacific Command.

The incoming secretary of defense, Robert Gates, indicated to the Senate Armed Services Committee in a prepared statement on Nov. 28 that he would continue those exchanges. "I believe that expanded military exchanges with China can be valuable but should be based on China's willingness to reciprocate."

The reasons for the exchanges are several. At the workaday level, the Chinese are learning "best practices," or how things are well done, says Brice-O'Hara. Strategically, the Pacific Command seeks to reassure the Chinese, who are suspicious of foreign powers, that the U.S. is not planning to attack. Conversely, the U.S. seeks to deter the Chinese from miscalculating and planning a war with the U.S.

In a related exchange, Secretary of the Treasury Henry Paulson is scheduled to lead a high-powered delegation to Beijing this week for the first meeting of the U.S.-China Strategic Economic Dialogue. His delegation is to include Secretary of Commerce Carlos Gutierrez, Secretary of Labor Elaine Chao, Secretary of Health and Human Services Mike Leavitt, Secretary of Energy Sam Bodman, and U.S. Trade Representative Susan Schwab. The chairman of the Federal Reserve board, Ben S. Bernanke, is to join the dialogue.

Down at deck level, the Coast Guard cutter Rush called at the Chinese port of Qingdao recently to pick up an official of the Fisheries Law Enforcement Commission, Tan Lizhou. He came aboard to work with the crew as they checked on whether fishing boats in the North Pacific were operating in accord with international agreements intended to conserve dwindling fish stocks.

"We made him part of the crew," said Capt. Dana Ware, then the skipper of the ship. He assigned Tan the rank of lieutenant commander, which made him relatively senior among the ship's 20 officers. Tan mustered to quarters, ate with the officers in the wardroom where he didn't much care for American food, and had computer connections with his home base in China.

Tan's main duty, however, was to communicate by radio with Chinese fishing vessels that Ware thought should be inspected, then to go with the boarding party to verify the vessel's registration, equipment records and catch log. "We let him do most of the talking," Ware said, noting that Tan's English got better as time passed so that he could explain more to his American hosts.

An e-mail to Tan asking whether his voyage aboard the Rush had been worthwhile and served the purposes of his government went unanswered.

Ashore, port security has taken high priority since the 9/11 attacks. The prospect of having a terrorist hide a bomb somewhere in a shipment of Chinese exports to the U.S. causes anxiety — as does a shipment of imports into China from anywhere.

Thus, says Adm. Brice-O'Hara, "We want to see their port security standards. And the Chinese come look at our ports so that we can share best practices."

Richard Halloran is a Honolulu-based journalist and former New York Times correspondent in Asia. His column appears weekly in Sunday's Focus section.