By Roland Buerk
BBC News, Tokyo
**Campaigning is formally getting underway for a general election in Japan that could see an historic change of power.**The Liberal Democratic Party of Prime Minister Taro Aso has governed for more than half a century with only a single break of less than a year
But it is trailing in the opinion polls with voting due on 30 August.
For the opposition Democratic Party of Japan there is a real chance of unseating the LDP and Mr Aso.
He is unpopular and behind in the polls.
Japan has been wracked by its steepest recession in decades.
Even though the latest figures show the economy is now growing again, Mr Aso admits few have felt the benefit yet.
The Democratic Party of Japan led by Yukio Hatoyama wants to shift the focus of Government from supporting corporations to helping consumers and workers - challenging the status quo that has existed since the end of the Second World War.
There are pledges of generous allowances for children, pension reforms and tax cuts.
But the opposition has offered few explanations of how to pay for the plans beyond eliminating waste.