The polling is nothing like what Nate Silver does, but Kyodo is out there, asking.
There is talk that in the multi-party contest, LDP will actually get as many as 300 seats. DPJ is going to deflate, and the other big third parties won’t get much more than a couple dozen seats.
Having LDP in there again is probably going to be bad news. There were a lot of problems in Japan when DPJ took over in 2009. Hardly anything got fixed. Now the screwers-up are going to be rehanded the nominal power to run Japan. (The actual power is in the shadows.)