Manga is a central part of Japanese pop culture, appealing not only to kids but also to salarymen and women on their daily commute. Even former Prime Minister Taro Aso declared his love for the medium.

If you think smartphones have replaced these comics as the commuter's time-killer of choice, take a closer look — you'll notice that many people are simply reading manga digitally on their devices.

Japan's print manga market is huge — seven times larger than that of North America. There are comics aimed at children, at adults and even at the elderly. The major weekly manga omnibus magazines, priced at around ¥300, bundle newly drawn episodes of about 20 different manga titles per issue. The most popular of these, Weekly Shonen Jump, prints 2.7 million copies every week, making it the nation's highest-selling magazine.