[@Letter Bee]
I mean, again, I am aware of the numerous areas where they could likely have been sold out by the Russians - though I think the Tokugawa Shogunate's "Expel the foreigners" ideology would not have tolerated handing Nagasaki over to the Russians in any way, shape, or form. They forbade the construction of ocean going ships on pain of death and only allowed the Dutch to enter Nagasaki, I doubt they'd let a different country take control altogether.

That is to say, yeah, it's fairly unlikely. Maybe it could have happened. Probably not. I would argue mine, likewise, has a "thin thread of possibility" that makes it a fun concept to explore. If I wanted to argue for a dry academic take on the "most likely" route for history to take I wouldn't be on a forum RP board I'd be arguing against a bunch of old men who still insist on having things faxed to them instead of emailed. 

Bad harvest is good with me if it is with you. It avoids the population crash issue of a plague. It provides context for the land reforms, as well as extra motivation for wanting to seize more land outside of Japan.