Rakuten is a huge internet presence, but isn't part of the publishing industry there-curious what their approach is going to be. Sony just re-entered Japan's eBook market last year, and Amazon is rumored to release the Kindle there next year.
Interesting article about the state of eBooks in Japan here
Japan’s book distribution system is unique, and perhaps the most influential factor in publishers’ reluctance to embrace e-books. In 1953, the Japanese publishing industry established fixed pricing for books and magazines. Under the current system, the major and established publishers enjoy higher status than foreign publishers. Fixed pricing for print media is tolerated despite the country’s anti-trust policies, but not when it comes to digital content. Overall, physical book distribution in Japan is suffering from a number of factors, including a 40% return rate, 28% decline in small bookstores, and an overall market decline of 17% since 1996.