I have just switched in my computer only to notice that Fukuda had a press conference five hours ago to express his resignation. It was just one year ago when Abe did the same.

After two pupulist prime ministers, Koizumi and Abe, Fukuda's lackluster style never mobilized people's support.
The ruling party, Liberal Democratic Party (LDP), had lost majority in the Upper House of the Parliament to make Fukuda's rule extremely difficult.

He was facing big problems for coming autumn. One is a possible general election.
His coalition partner Koumei Party, a buddhist party, wants to have the election held toward the end of this year. For various reasons this is the only suitable time for that party.
For this they needed more popular prime minister to fight with.

The opposition party, Democratic Party, has been pushing for an early election. Recently several leaks have been done to discredit one of Fukuda's cabinet members and Koumei Party (just yesterday the most populous Yomiuri newspaper carried a top story about machinations by LDP and Koumei Party.)

Probably former foreign minister Aso, currently General Secretary of LDP, will be elected in the Parliament as next prime minister. His stance is rather hawkish and he will probably promote prolongation of the temporary law, which made possible the Self-Defense Forces' cooperation with the allies in anti-terrorist warfare in Afghanistan ( by refuelling their warships on the Indian Ocean).

The prolongation is much needed to keep Japan's credibility as ally in the eyes of Americans, but for the pacifist Koumei Party it is an undesirable act, especially on the eve of a general election.

Let us see what will happen. It is getting exciting. The Japanese are also demanding a "change".
Though the opposition Democratic Party does not enjoy much trust, either, many voters might bet for a change. Economy is not in a bad shape. Japan can afford a change now.

(But I do not think that a mere change of the ruling party will be able to bring needed reforms in the society. We are being deeper and deeper bogged down in populist politics.)