Now this should signal a brand new dynamic in the Asia-Pacific region. New Japanese Leadership that affirms needs for strong ties with the US. An undercover (to an extent) public announcement of a renewed deterrent force to China's rise I suspect.
Quotable Quotes - "On foreign policy, he said ties with the US were a priority.
But he said he wanted a relationship in which Japan "can act more proactively and tell them our opinions frankly", adding that his party's position on reviewing deals relating to the US troop presence had not changed." Japanese Prime Minister Yukio Hatoyama
New PM cements Japan power shift
Japanese Prime Minister Yukio Hatoyama promised economic revival and strong US ties, hours after taking office.
Source - BBC 16 September 2009
In a news conference, he vowed to deliver a "people-oriented society", quick economic improvements and frank but trusting ties with Washington.
Mr Hatoyama's Democratic Party of Japan won a huge poll victory last month, ending 50 years of almost unbroken Liberal Democratic Party rule.
His untested government now faces tough economic and social challenges.
The new cabinet will be sworn in by Emperor Akihito later in the day.
Former DPJ leader Katsuya Okada becomes foreign minister and Hirohisa Fujii, a veteran bureaucrat, takes over as finance minister.
Another former DPJ leader, Naoto Kan, will head a new National Strategy Bureau set up to oversee the bureaucracy. He also becomes deputy prime minister.
The defeated LDP, meanwhile, will hold an election later this month to choose its new leader, after former Prime Minister Taro Aso stepped down.
The DPJ has entered into a coalition deal with two smaller parties, the Social Democratic Party and the People's New Party, and controls both houses of parliament.
Its priorities now include tackling a rapidly ageing society and an economy still struggling after a brutal recession.
"We would like to carry out policies that will stimulate households so the Japanese people can have hopes for the future," Mr Hatoyama said.
He has promised to increase social welfare spending, cut government waste and rein in the powerful bureaucracy.
''Now is the time to practise politics that are not controlled by bureaucrats,'' he said.
On foreign policy, he said ties with the US were a priority.
But he said he wanted a relationship in which Japan "can act more proactively and tell them our opinions frankly", adding that his party's position on reviewing deals relating to the US troop presence had not changed.
The DPJ was elected as a wave of discontent with LDP rule swept across Japan.
Opinion polls have shown many people did not vote for the DPJ because of their policies - but because they wanted change.
Analysts say the electorate will be watching the DPJ closely in the next few weeks and months to see if it can deliver.
The BBC's Roland Buerk, in Tokyo, says that in defeating the LDP, Yukio Hatoyama has already achieved what many people thought for years was impossible.
But now the difficult part - governing Japan - begins, our correspondent says.
Roland Buerk, BBC News, Tokyo
Yukio Hatoyama looks like many who have gone before him, the scion of a wealthy dynasty, the grandson of a former prime minister. But his DPJ has promised profound reform.
For decades the LDP, bureaucrats and big business held sway, steering the country from wartime defeat to economic might. But in recent years this brought stagnation, rising unemployment and increasing inequality.
Mr Hatoyama wants to build a more 'fraternal' society, with a social safety net including a generous child allowance to try to encourage people to have children and arrest Japan's declining population. He wants to turn away from export-led growth and encourage domestic demand.
But there are deep concerns over whether the untested new government can deliver the new era they promise.