With gas prices the way they are, more parents in Japan are biking their small kids to school. In Japan's very compact cities, most folks tend to live quite close to their kids' preschool or kindergarten.
So the Kawamura Cycle Company came up with a "bicycle built for three" that's a lot safer than the conventional approach of tacking on an aftermarket child seat. As you can see in the photo below, another of the bike's selling points is the rear-wheel configuration, designed for stability even when riding over the bumps and other obstacles that are so common on city streets.
My kids are too old to sit in back, but those child seats look to be just the right size for a small sake cask.