Although it has now been surpassed by the United States, Japan was once the world's largest market for e-books, thanks to the early success of the cellphone-content business. But in today's competitive market, e-book sellers disappear every few months, leaving consumers to wonder whether the digital products they are buying are as permanent as paper books.

Japan has many platforms that sell e-books, run by distributors, cellphone carriers, electrical-goods retailers and so on. When you consider Japan's literacy rate, long train-commute times that afford time for reading, and the huge size of the paper book market, e-books make for an attractive business proposition.

On May 29, Yamada Denki, Japan's largest chain retailer of electrical appliances, announced that it will close its Yamada e-Book store at the end of July, two years after its launch in June 2012. The service is not especially popular anyway, but the announcement raised the hackles of users by saying that all their purchased e-books would become unavailable; that unused credit would not be refunded; and that Yamada Denki will eventually start another e-book store.