What the heck? Disagree with them as I do, I'm as baffled as the Daily Yomiuri on this one. He had been frustrated by the DPJ's attacks on Japan's role in Afghanistan, yes, but that seems an insufficient reason.
The Japan Times suggests that it may be health issues, though. That makes more sense, but one does wonder what, exactly, those might be. Certainly the Japanese public does, faced as they are with a leadership vacuum... and the Liberal Democratic Party that Abe led probably does as well, as I don't see them having a clear successor in mind.
(Which is absolutely unprecedented in Japanese politics. As in, "since they've had democracy" unprecedented.)
The scuttlebutt suggests that Taro Aso might be the next PM. That, er, would be slightly problematic for Sino-Japanese and Korean-Japanese relations. "Giving Ted Stevens the presidency" problematic. Here's hoping someone a bit more reasonable gets the post.