Here is the Hyper Convenience U.S. Mart, part of Shinjuku's American Blvd. I passed this area while walking to a nearby movie theater to see the anime Brave Story (it turned out to be pretty crummy). A general rule is that anything which claims to be American in Japan will actually have no relation to the United States at all. This store didn't carry any American-made products and I am certain that the staff didn't speak a word of English.