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At airports and major train hubs in Japan, you can often find KitKats that you can't find elsewhere. This is an old picture, so I doubt that all of these are still available. The first one on the left is a white chocolate soy sauce variety. Next to it is a kinako one then a strawberry "Rilakkuma" one and then green tea.
The Rilakkuma one is no different than the seemingly dozens of strawberry Japanese KitKats that have been released through the years. It's called "strawberry milk", but the addition of "milk" is almost certainly meaningless when it comes to the taste. I think strawberry, and to a lesser extent, cherry, are Nestle Japan's "lazy" flavors. When they want to release a variation because of a hook up with a T.V. show or popular character, they must sit in the office wracking their brains about what flavor to attach to it. For Rilakkuma, they probably considered "honey", "fish", and even "pine tree", then ultimately threw up their hands and decided to just make it cherry because people would buy anything as long as the cute little "Hello Bear" character was slapped on the package.