Home key? We don't need no stinkin' Home key!
Since the Paperwhite is lacking handy things like...er...buttons of any sort, they set it up so you have to simultaneously tap the upper-right and lower-left corners of the screen to take a screenshot, so that's what I did.
Getting the screenshot to take before it dismissed the expanded conversions panel was tough, but having the regular keyboard displayed was no problem.
BTW, I've now got the Paperwhite jailbreak
, screen saver hack
, easy-peasy font "hack,"
and the Collections Manager hack-oid
running on this device, so it looks to be perfectly compatible with non-Japanese customizations too. It really appears to just be exactly the same machine; this is so rare in Japan that I'm still befuddled by it.