Well, embarrasingly, after going on and on about how I love onigiri (and I do), I learned the real way to open them the other day. It's SO easy and obvious, and makes the package come out perfectly neatly.
And in this post, the shrine thingies I thought might be family memorials? Nope, probably not. I asked a Japanese friend (and I'm smiling to type that) and she looked at my pictures, and though not totally sure, said the ones she saw are stones with the names of kami, or Shinto gods.
I bought my shinkansen (bullet train) ticket today. A new adventure tomorrow!