Originally Posted by sirmaru
If one has a Japanese Kindle and does a Device Reset (eliminating its registration on the Japanese Amazon Store) and then, inside the US territory, registers it at the MYK page at the US Amazon Site, would the Amazon US Store appear in the Kindle?
I very much doubt it. My understanding is that the Japanese PW has different firmware to the US version, and that firmware almost certainly won't be able to access amazon.com.
I bought a Kindle Touch from the US when it was first released, because it wasn't available in the UK at the time. Although it worked fine in the UK (I was able to register it to my Amazon UK account, download all my books from the Archive, etc) the one thing it wouldn't do was access the Amazon UK bookstore. It only gained the ability to do so once the Touch was officially released in the UK and there was a firmware update which added access to the various national Amazon stores.
So no, I would not expect a Japanese PW to be able to access the US bookstore.