One of the original planks in the Democratic Party of Japan's 2009 platform, or manifesto as it's normally called, was an overhaul of social security. Acknowledging that the national pension system was irreparably broken, the DPJ proposed tossing the old pay-as-you-go "insurance" model and replacing it with a system that paid benefits completely out of tax revenues. Upon retirement, every qualified person would receive ¥70,000 a month until they died.
With Kaoru Yosano assuming the position of fiscal and economic policy minister in the newly reshuffled cabinet, that proposal is all but doomed. Yosano, who is against ditching the premium system, filled a similar cabinet position under the last Liberal Democratic Party prime minister, Taro Aso, so it's not likely he's going to change his mind even while toiling for the DPJ. In fact, Prime Minister Naoto Kan implied only a few days ago that the social security plan in the manifesto is not realistic.
What he means is that it's not realistic politically. Practically speaking, it's certainly more realistic than the present system, which the welfare ministry favors because they think it's more clearly ethical when it's really anything but. To receive benefits after retirement, one has to pay into the system at least for 25 years. If you pay for only 24 years and 11 months, you get the same benefits as someone who paid nothing: ¥0. (In comparison, in order to qualify for minimum social security in the U.S., you have to pay SS tax for at least 40 quarters, or ten years)