For now, only a couple of handfuls, if the Asahi is to be believed. We’ll know in a matter of hours, if not days, but in the meantime, here are a few thoughts around the report that may be useful beyond the immediate future.
So far, prospective defectors are small in number and are mainly (but not exclusively) first-term Ozawa children (Miwa is a ripe old 69) in the lower house representing the urban expanse between the true outback and the Tokyo/Nagoya/Osaka metropolitan. No upper house names have emerged.
How will they fare in a snap election? Intuitively, not so good. They will have to share the anti-consumption tax hike vote with Your Party, who will also be able to 1) run candidates in more districts, which will help it gather proportional votes, and 2) position itself as the reformist alternative. There are many other factors to be considered, some positive (Yasunori Saito, who has local celebrity status, will rake in votes outside his district; people like Nobuaki Miwa, who have independent political capital, maybe able to wrest away a larger part of the local DPJ chapter than otherwise possible), some negative (political novice rookies may not be able to take much of the local DPJ party machine away with him). All things considered, expect a few other multi-term Diet members as well a rookie or two that have strong local assembly backgrounds to make the leap, calculating that, at worst, they can slip back in on the proportional tickets. Conversely, pure political rookies will not jump ship unless Ozawa jumps with them.