Okay have the Japanese never heard of Country music? When programming the "type" of station there is not a country type. Maybe no one else listens to country music anymore, I don't think so. Is this something that could be upgraded?
I have found that the RDS search (at least in Los Angeles) will classify "country" stations in the Rock category. It may very well not be the Japanese not providing a classification for it, but the RDS system may have a limited caregory designation. Why else would Classical and Jazz ever be put together?!