Does anyone have experience reading Japanese light novels on the Amazon Kindle (especially the Paperwhite and Oasis)?  

Are many light novels available? 
Can you access the dictionary while reading the novel? 
Can you purchase Japanese light novels for Kindle using an overseas credit card?

Yes.

Yes. Get one of the EDICT dictionaries for 500 yen.

Yes, but you need a Japanese address. And you should also use a VPN. It's really tricky, and you could still get your purchase declined. There's a thread about it on here somewhere. Amazon probably knows you're buying from overseas anyway, and is choosing to look the other way, but I have no clue how it works. I don't think anyone else does, either. (But if someone has recent concrete knowledge, please drop it on us!)

There's also the BookWalker app on Android, that has one of the publishers' LNs and manga, Kadokawa I think? You can buy LNs without worry from them from overseas, or so I hear. I haven't used the app myself, though.

TBH, I've gone back to reading paper books. It's less hassle.

Actually you don't even have to pay for EDICT, you can just install this one from Github. That's what I did at least.

As for the availability of light novels, I suggest you check the amazon page first.

Oh, and the Kindle has a Vocabulary Builder function that remembers the words that you looked up and stores it in an SQL database. Since I wanted to use Anki instead of the Kindle's built-in flashcards, I was able to write a script to extract the words from it so I could create cards using Epwing2Anki. That was huge in helping me build up my vocabulary.

Even without installing a dictionary, there are two japanese dictionaries by default, one j-e and one j-j.
When you underline a word or sentence you can save it and then you can go to kindle.amazon.co.jp and you'll se a list of all words and sentences you saved.

Edict2Kindle looks interesting. If I had known about it, I might have used it when I got my Kindle a while back. The J-E dictionary on the Kindle is okay, but EDICT has better coverage for reading, from my experience using both.

That script sounds pretty cool. I don't suppose you have a link or a way to make it public? I can get at my Vocab builder database using a SQL viewer, but it's a pain in the butt to do it that way. Did you write something in python or similar to scrape the database for the fields you wanted? (And are the example sentences stored in the database as text, or are they referrals to the actual data files? Because I could never find those.)

(2016-05-14, 9:54 pm)rich_f Wrote: Yes, but you need a Japanese address. And you should also use a VPN. It's really tricky, and you could still get your purchase declined. There's a thread about it on here somewhere. Amazon probably knows you're buying from overseas anyway, and is choosing to look the other way, but I have no clue how it works. I don't think anyone else does, either. (But if someone has recent concrete knowledge, please drop it on us!)

Hmmm, I didn't find it to be much of a hassle after the very first set-up. Though the first set-up was rather awful, that's for sure.
But yeah, I think there's some issues with publishing rights or something and that's why they usually wouldn't sell ebooks overseas. So it is some kind of "Amazon looks elsewhere" case.

If you still want to try, this is what I did to set up my kindle:
1) use another e-mail address for your amazon jp account (I personally just used an alias address, your e-mail provider might support that as well https://support.google.com/mail/answer/12096?hl=en )
2) set location to Japan on Amazon jp
2.1) input a Japanese address - I input a tenso address (though I never reallly used the tenso forwarding or even went through the authentication procedure), some people seem to input random or hotel addresses (I just didn't feel comfy with that idea - and who knows maybe I'll need a tenso address for something else in the future)
3) input credit card info (for me it's a non japanese one - didn't run into any problems there)
4) connected kindle to the amazon jp account (using the adress from step 1)

I think I bought my first ebook through the website way back, after that it definitely wasn't a problem to buy it from the reader directly. I never ever used a VPN for that.

I think on step 4 it told me something like, "you might not be able to use your other ebooks on the reader anymore", but if you find that is the case, you can always just change the account back to your old one. I don't have many other ebooks on there, but I could access mine just fine. Though when I switch to my non-jp account (because I want to buy something on the store which I couldn't find on the jp store) I can't access the jp books anymore (they are still there, I'm just denied access until I switch back to the jp account). Apparently JP is a bit stricter there.

If you are worried about your current ebooks, apparently there's also a way to back them up ( http://ebookfriendly.com/back-up-kindle-books-2-ways/ )

By the way you can still set up a non-japanese-address as a second address on amazon jp without problems, if you want to order physical stuff to your regular address.

Yeah, that's exactly what I've been doing, and I haven't had any problems either, but other people had done the same thing and had gotten emails demanding proof of residency (like a copy of a gas or electric bill) after downloading 5 books from foreign IP addresses. (That was a year or two ago, I think.) Maybe they've changed their policy since then.

I've been using a VPN just as a belt-and-suspenders approach, but I also haven't had any problems, either. (Other than using a VPN on an aging Motorola Xoom to order books, which is as painful as it sounds.)