"The purpose of the visit is to sustain the very positive momentum that we've seen in the US-China military relationship over the past year and a half," an unnamed senior defence official told Xinhua.

Pentagon spokesman Steve Warren said the two would discuss a variety of issues, including the Sino-US relationship in general as well as military ties.

Chang's itinerary includes a meeting with Admiral Samuel Locklear, commander of all US military forces in the Pacific, in Hawaii on Friday. Chang will meet General Charles Jacoby, commander of the North American Aerospace Defence Command and US Northern Command, at their headquarters in Colorado Springs, Colorado.

The visit is Chang's first since he took up the post in March. Analysts believe the minister, who is described as a friendly and skilled diplomat, may be the right person to bridge the divide between the two superpowers.

With a solid background in the PLA and labelled "top future leader to watch" by the Brookings Institute think tank, Chang is seen as another manifestation of Beijing's more amiable leadership style of late.

Such skills will prove helpful given the gravity of issues to be discussed, notably China's maritime expansion.

"The US will encourage China to be more open about its strategic intent," said Dr Alexander Neill, a senior research fellow at the International Institute of Strategic Studies. "Beijing has generally portrayed Taiwan as its [justification for an act of war] but lately this has become a smokescreen for a broader agenda, notably the blue water arena in the Pacific and other oceans."

Another sensitive topic is cybersecurity. Following the revelations by Edward Snowden, a former contractor at the National Security Agency, the computer hacking and electronic espionage carried out by both sides might be the elephant in the room, Neill said, and talks were likely to be limited. Despite this, the US would be keen to discuss the nature of China's intent in these and other strategic issues.

"China's economy has supported a big increase in military spending on a more capable military that can operate further from China's shores," said Dr Phillip Saunders, director of the Centre for the Study of Chinese Military Affairs at the National Defence University in Washington.

"The question is what will that military power be used for? If China attempts to dominate Asia or intimidate US allies, that will be a problem," Saunders said. "If it's focused on defensive capabilities, that's less of a big deal."

Chinese leaders, in return, are nervous of American rhetoric about its military "pivot to Asia" and may demand a clarification on what this means, not least regarding the US stance on possible conflicts in the Pacific region.

Ni Lexiong, director of the Sea Power and Defence Policy Research Institute at Shanghai University of Political Science and Law, said both Beijing and Washington were keenly aware of the need to step up military exchanges as a major conflict was is in neither party's interest.

"Both nations want to deal with domestic issues more, and do not want chaotic situations in the Asia Pacific region," he said.

Yue Gang, a retired colonel and military commentator, said both militaries wanted to address their "trust deficit".

"The trust between the two militaries lags seriously behind economic and trade co-operation between the two nations," Yue said. "Both sides are attempting to manage their differences."

Yue expected that the two sides would discuss setting up of a notification mechanism for major military activities, as agreed in the recent Sino-US strategic and economic dialogue.

"But it is not expected that such system will be implemented immediately," Yue said. "It would take time for the two sides to agree on what constitutes 'major military activities'," he said.

The best both sides could hope for now might be increased access to decision makers, said Oliver Bräuner, researcher at the China and Global Security Programme at Stockholm International Peace Research Institute.

"The meeting should focus on stabilising and institutionalising the relationship, and make sure that it's not so vulnerable to US-Taiwan relations," he said.