If you are staying in Japan and looking for something to read while you are on Shinkansen, please visit a book store.
Book stores in Japan are divided into two types. The first one is the family run store which has solo or multiple stores in a single municipality or its surrounding. The second one is stores which has multiple large stores in various big cities. Family one is basically located at residential area but large stores located at business centers and department stores.
Although there are book stores located at stations but not so many are located beyond the ticket gates, which customers should have valid train tickets to pass the gates. Therefore, if you want to buy some books, better to visit large stores which sell books written in English located in large commercial districts.
Jinbo-cho, a district in Chiyoda ward, Tokyo is a book store district including used books.